It gets better. This new PC, called Zonbu, from a new company of the same name, automatically receives free updates of its software when new versions come out. It doesn’t require antivirus or other security programs because it runs on the Linux operating system, which has attracted very few viruses or spyware programs. And it takes up almost no room — it’s a tiny little box.

Zonbu’s overall goal is to vastly simplify the process of buying and using a computer. The idea is to make it not only more affordable, but also much less of a hassle and much more energy efficient.

I’ve been testing the Zonbu, and it does work. Its software is still in beta, or test, mode until next month. But you can buy it right now at Zonbu.com with free software updates into the future. However, there’s a catch — several catches, in fact. Some have to do with the machine’s design and pricing, and others with its performance. Taken together, they prevent me from recommending this computer, despite its intriguing price and concept.

The biggest catch is that the Zonbu computer doesn’t include a hard disk for storing files (that’s one reason it uses so little energy). Instead, all of your files are stored online on the company’s servers. That offers several advantages, such as the fact that the files are automatically backed up.

But you have to pay for that online storage. In fact, to get the $99 price for the Zonbu computer, you have to commit to a two-year contract at prices ranging from $12.95 a month for a relatively small 25 gigabytes of storage to $19.95 a month for 100 gigabytes. If you opt to pay month to month instead of two years in advance, the Zonbu will cost you $249.

To get the Zonbu for $99 with 100 gig-abytes of storage, it will cost you $517.95 up-front after the discount of three free months that the company is currently offering. And the Zonbu doesn’t come with a monitor, keyboard, mouse, Wi-Fi adapter, speakers or DVD drive.

By comparison, you can get a Dell Inspiron 531s for just $529, after rebate. It has twice the memory, a DVD drive and a much better processor than the Zonbu. And it comes with a screen, keyboard, speakers and mouse — oh, and a 160-gigabyte hard disk that requires no monthly fee.

To be fair, the Dell doesn’t come with a full-fledged office productivity suite, while the Zonbu has OpenOffice, a competitor to Microsoft Office, preloaded. To get OpenOffice on the Dell, you must download and install it.

Also, the Zonbu monthly service fee is offset by some savings. The $99 machine uses so much less energy than a typical PC that the company claims you could save noticeably on your electric bill. And you might also save the cost of subscribing to security software updates.

Zonbu

Because the Zonbu stores your files on a remote server, you can also use them remotely, at no extra cost, from another Zonbu or from any Windows PC.

To speed things up — and guard against an Internet service outage — the built-in programs are stored locally on the computer, and Zonbu includes a small 4 gigabyte memory card in the machine to cache your documents. In my tests, this allowed me to keep using the Zonbu even when I unplugged it from the Internet.

In addition to OpenOffice, the Zonbu comes with the Firefox Web browser, an Outlook clone called Evolution, an iTunes clone called Banshee, the Skype Internet phone software, and a bunch of other programs for organizing photos, playing video and more. There are also some casual games.

To Zonbu’s credit, the machine is capable of recognizing lots of printers and digital cameras, out of the box. It worked well with my Kodak camera and Hewlett-Packard printer.

But there are three other big problems with the Zonbu, problems that belie its goal of eliminating hassles. First, you aren’t allowed to install any added software. You’re stuck with what the company provides. And that means, for instance, no video-editing software, for now at least.

Second, a lot of this Linux software is rough, below the polished level of Windows or Mac programs. In my tests, various programs crashed or froze frequently. While the Banshee program is supposed to work with iPods, it failed to work properly with both of the iPods I tested.

Finally, I found that the Zonbu crawled much of the time. Folders took forever to open, email took way too long to appear, and so forth. And I was testing it on a very fast Internet connection. This may be because of the very wimpy processor Zonbu uses to save money and energy.

I strongly support Zonbu’s goals of making computing simpler, cheaper and more energy efficient. But this product has too many compromises.

• Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital Web site, http://walt.allthingsd.com.

Clearly, many people are furious about these unwanted programs and icons, which are sometimes called craplets. Many would like to smite them without going through the laborious process of uninstalling them manually, one at a time. Some readers suggested strategies. The following are some options.

One ray of hope is a free program called PC Decrapifier. It can be downloaded at pcdecrapifier.com. This software automates the process of uninstalling craplets. It was written originally to clean up Dell computers, but its author says it will work on other brands, too. Before PC Decrapifier runs, it allows you to remove from its proposed deletion list any programs it considers junk, but which you might prefer to retain.

I haven’t tested PC Decrapifier, but even assuming it works well there are a couple of downsides. First, it may not remove every craplet from every manufacturer. Also, unless you carefully tweak the deletions list, PC Decrapifier might remove some full working copies of preinstalled software that you want; it can’t easily differentiate between trial and real versions of some commonly bundled programs.

Another option is to order a PC without the craplets in the first place. Some high-end Dell gaming machines are sold this way. Dell says you can also opt out of some third-party software on other models. Certain business models from various makers can be purchased clean, as well. But even business machines sometimes come with unwanted trial software, like limited versions of accounting programs, and may not be configured for consumers.

Dell, Sony and others say they are moving toward a new scenario in which all of this stuff will be easily refused on all models.

An alternate strategy is to avoid brand-name Windows computers and buy a Vista PC from a local shop that will construct it to your specs and leave off all the craplets. The catch is that you may pay more, and you must be certain that the shop will be around and willing to provide support for the life of the machine.

Some techies wrote me to say that the first thing they do with a new PC is to wipe out the hard disk and reinstall Windows so they start with a clean machine. But I can’t recommend this for average users. For one thing, many new PCs no longer come with disks for reinstalling a full, clean version of Windows. Some have special sections of the hard disk from which you can perform a “recovery,” but these recoveries may not be complete or may reload the craplets along with Windows. You could, of course, buy a fresh copy of Vista to reinstall, but that could cost hundreds of dollars.

Also, wiping out and rebuilding an operating system can be tricky for nontechies. Dell told me, “It is not advisable for nontechie consumers to wipe the hard drive and reinstall. … This is intended as an emergency backup or for the technically sophisticated.” Sony and Gateway sent me similar warnings.

Finally, an excellent way to avoid or minimize the craplet problem is to simply buy an Apple Macintosh computer. New Macs don’t have any craplets displayed on their desktops. On a new Mac, no third-party software is automatically launched when you start the computer, and you don’t need antivirus or antispyware programs because the Mac is essentially free from those menaces. So, even my year-old Mac laptop reboots roughly three times as fast as my three-week-old Sony.

Apple does include a few third-party programs on Macs, including one that, oddly, is for drawing comic-strip effects on photos. But these are tucked away in the applications folder and most are full working versions, not trials or offers. The main exception is a trial version of Microsoft Office. With some Mac models, you get trials of two Apple programs, iWork and FileMaker Pro. But these trials can be deleted simply by dragging the icons to the trash can.

Computer makers should stop dumping craplets on us. Until they do, you can find ways to avoid them.

• Email me at mossberg@wsj.com. See video versions of my reviews at wsj.com/mossbergvideo.

You need a good antivirus program, a strong firewall program, an effective antispam program, and a program that specializes in stopping spyware and adware. Or you could just buy an Apple Macintosh, which isn’t significantly affected (so far) by these threats, other than spam email.

But the fastest-growing computer-security problem isn’t viruses or other traditional malicious programs, and it can’t be entirely defeated by using security software or by buying a Mac. It’s called “social engineering,” and it consists of tactics that try to fool users into giving up sensitive financial data that criminals can use to steal their money and even their identities.

Social engineering is a broad term that includes “phishing,” the practice by which crooks create emails and Web sites that look just like legitimate messages and sites from real banks and other financial companies. It’s closely linked to a newly named category of malicious software called Crimeware — programs that help criminals steal your private financial information.

These terms are confusing and overlapping, but the threat is real. Increasingly, common-looking scams are combined with secret installations of software that help criminals spy on you and steal your data.

Here are a few tips to help you avoid these schemes:

1. Don’t trust email from financial institutions. Email is so easily manipulated by crooks that you simply should never, ever consider any email from a financial institution as legitimate. The message may bear a bank’s or a broker’s logo, but you should never respond to such an email, and never click on any link it contains.

There is a very high chance it’s a skillful fraud, and that the link will take you to a clever fake Web site designed to capture passwords and account numbers. The site may also silently install on your PC a program called a key logger, which records everything you type and sends that information back to the crooks.

2. Never respond to unsolicited commercial email, or spam, or even click on a link in an unsolicited commercial email. In the old days, responding to spam just got you on more spam email lists. Today, it might also result in the secret installation of a key logger or other malicious software.

Besides, any company that has to resort to spam as a sales tool isn’t likely to have a very good product to offer. Do you really think that if someone had invented a pill that enlarged penises and breasts, he’d be selling it through spam? He’d have sold it to a big drug company for billions. And nobody in Nigeria needs your bank account to store stolen millions.

Would you buy a stock touted on the street by a complete stranger? If not, why would you buy one touted in a spam email?

The only safe response to spam is to ignore it and delete it.

3. Don’t download or use free software unless you’re sure it’s legitimate. Sites offering free cursors, for instance, can secretly install all sorts of bad stuff on your PC. This is especially true of free security software, which is sometimes just malicious software posing as a security program. If you suddenly see a security program pop up on your PC, don’t trust it.

There are many legitimate free programs, including some good free security programs, like SpyBot or AVG Anti-Virus. But check them out before downloading. Look them up on the CNET or PC Magazine Web sites, which review most software. If they’re not covered there, assume they’re not legitimate. You may pass up some free programs that are real, but it could save you from huge grief.

Earlier, I said that buying Windows security software, or using a Macintosh, can’t automatically protect you from social-engineering schemes, and that’s true. But they can help. An antispyware program can’t prevent you from entering sensitive information on a fake Web site, but it might block the installation and operation of spying software from that site. A Macintosh owner can foolishly give up her bank account number, but most malicious software that crooks try to install won’t work on a Mac.

And there are some new security programs aimed directly at social-engineering scams. McAfee’s Site Advisor program can tell you if a Web site seems bad. A new add-on for the Firefox Web browser, called Shazou, can tell you where a Web site’s server is located. If you think you’re on the Bank of America Web site, but Shazou tells you the server is in Russia, that’s a clue that you’re being scammed. And Symantec plans a new product this fall called Norton Confidential that will tell you if a Web site appears to be a fake. Also, forthcoming new versions of Firefox and of Microsoft’s Internet Explorer browser will have built-in warnings that sites may be fake.

The best defense against social engineering, however, is to be smart and careful.

• Email me at mossberg@wsj.com.

The result is that criminals can use the browser as a gateway to plant all kinds of bad software on your PC and to steal your personal information by accessing your files or recording what you type.

Today’s common defenses are hit or miss. You can install antivirus and antispyware software, but those must be updated constantly to recognize new attack patterns, and sometimes the bad guys get ahead of the defenders.

Now, a small Silicon Valley company called GreenBorder is trying a radical approach. It has developed a product that isolates the browser from the rest of the computer, without impairing your Web browsing. It erects a sort of fence around the browser. Inside that fence, the browser runs normally, along with associated programs like media players. But the browser can’t be used to install bad software or to spy on the rest of the computer outside the fence.

With this product, called GreenBorder Pro, any malicious software you pick up is trapped in a computing environment — called a virtual session — that exists only inside the fence and can’t affect any key files or settings outside.

Once you quit the browser, this virtual session simply disappears, along with any bad stuff that has collected within it. Your files and settings remain unaffected. You can even purge the bad stuff from the virtual environment at any time by clicking on a command called Clean and Reset GreenBorder.

For instance, inside a GreenBorder Pro session, you might get infected with a “browser hijacker,” a spyware program that permanently changes your browser’s home page and search page to sites operated by sleazy companies. But once you quit the browser, or click on Clean and Reset, the hijacking effects disappear.

To show it’s protecting you, GreenBorder Pro places a literal green border around the browser. It also displays a summary of the malicious software it trapped inside its border and prevented from affecting your files and settings. If you deliberately choose to download a file, it gets placed in a special folder on your PC and marked with its own green border. It then runs in a protected session, just like the browser.

One big advantage of the GreenBorder Pro approach is that there’s no need to try to stay ahead of the bad guys’ techniques. GreenBorder doesn’t have to collect and update signatures of known bad programs.

GreenBorder Pro, available for download at greenborder.com, works only with Microsoft’s Internet Explorer browser for Windows, the most popular but least secure major Web browser. GreenBorder costs $50 a year, but is free for one year to the first 10,000 to download it.

I tested GreenBorder Pro on three different Windows computers, and found it easy to use. While it is difficult to test a negative, I deliberately used GreenBorder Pro to access numerous known bad Web sites, those that typically install unwanted adware and spyware on a PC.

Before starting, I ran both an antivirus and an antispyware scan to ensure each test machine was clean. I ran the scans again after quitting GreenBorder Pro, and the PCs were still clean, despite all those visits to bad sites. GreenBorder Pro reported that it had blocked dozens of attempted “file changes” and hundreds of attempted changes to the Windows Registry, the part of Windows that stores instructions for running software.

GreenBorder Pro has two other major features besides its basic function. One, called Privacy Zone, sets up a special browser mode for those times when you are visiting a Web site where you expect to be entering passwords or credit-card numbers. In this mode, the Clean and Reset process is performed automatically first, to purge any spy software that may be operating, and all traces of your Web activity are wiped out when you’re done. A yellow border is placed around the browser when you are in the Privacy Zone.

The second function is called SafeFiles. It lets you erect a fence around files from sources other than your browser, including email attachments and files you copied onto your PC. This is an extra-cost option priced at $14.95 a year.

There are some limitations to GreenBorder Pro. It won’t clean out existing viruses and spyware on your computer, or automatically block invasions that aren’t from Internet Explorer. You still need standard security software. It also won’t prevent you from being tricked into giving up private data. Also, some legitimate software downloads and installations will fail with GreenBorder Pro. You’ll have to run a browser in normal mode to get the downloads.

Also, I don’t see why you should pay $50 every year, instead of just once, for software that boasts that it doesn’t require updates. (The company says the annual payment covers better support and new features.)

But GreenBorder Pro is a novel and very promising weapon against malicious software.

• Email me at mossberg@wsj.com.