You might be able to get at the desired file if you have previously uploaded it to an online storage or photo-sharing service, or emailed it to yourself. But, in many cases, you could be stuck.

Now Dell (DELL), the big computer maker, is aiming to solve that problem with a new service called Dell Remote Access. Despite the name, the service can be installed on any brand of Windows PC running Windows XP or Windows Vista to make its files remotely accessible, as long as it has a broadband connection. You can transfer, or stream, or share these files with others. You can even remotely use the host computer’s Web camera.

And some of the service’s functions also work even if your remote device is one of Apple’s (AAPL) Macintosh computers or iPhones, or a computer powered by the Linux operating system, like Dell’s own Mini netbook.

For basic functionality — making the files on one Windows PC remotely accessible from other devices — Dell Remote Access is free. If you want to use its advanced functions, like the ability to remotely control the host PC or to access other devices on your home network, it costs $9.95 a month, or $99 a year. This paid version of the service also includes the ability to share with others access to files or to devices on your network, such as stand-alone Web cameras.

You only need to install special software on the host PC whose files are to be remotely accessed. For basic file access, the remote devices require just a Web browser and a password to tap into the host computer. You can download the software, and get started with the service, at dellremoteaccess.com.

I’ve been testing Dell Remote Access for a few days, at home and on the road, and found that it works well, despite a few glitches and limitations. It’s not revolutionary — many other services and software programs do part or all of what it does, with varying degrees of technical difficulty and at varying fees — but Dell Remote Access combines a wide variety of functions into a fairly simple package. It will be available as a preinstalled option on Dell’s PCs later this year.

Dell also is hoping it will give a boost to sales of its Mini line of very small machines with limited internal storage for files.

For my tests, I installed Dell Remote Access on my home Dell desktop, an XPS One model running Windows Vista. The installation was easy and quick, except for one oddity: To use the new service, you have to uninstall a network diagnostic utility Dell installs on its machines, called Dell Network Assistant. Since I had little or no use for the utility, this was no big loss, but if you rely on it, this conflict could pose a problem.

Next, I used the Remote Access software to select folders I wanted to make remotely accessible. By default, the program assumes you want to share your documents, music and pictures folders, but I added some others. The software tests your network connection to let you know how well it’s likely to work.

I used a variety of remote devices to access this home Dell. These included a Sony (SNE) Vaio laptop running Vista, a Mac laptop and an Apple iPhone. I even tried accessing the Dell machine from a virtual Windows XP installation running on the Mac.

Some of these tests were conducted from within my home network and others were conducted from across the country.

In general, the tests went well. With the Sony laptop, and within Windows XP running on the Mac, I was able to view photos and slide shows, and stream music and videos, from the Dell in all locations. I opened Microsoft Office (MSFT) files and PDF files remotely and transferred files to the remote machines. I was even able to remotely control the Dell at decent speeds and use the Dell’s built-in camera.

The only annoyance was that every time you want to remotely control the host machine, you must download and install a small utility. You also have to leave on your home computer.

Dell’s system provides more limited functionality if your remote machine is a Mac using Apple’s operating system, or a Linux machine or a mobile phone. With these setups, you can only view, stream or transfer files only from the main host computer. You can’t do remote control or view cameras.

But these limited functions did work pretty well on the Mac and the iPhone, although in some cases I had to first download a song to the Mac before it would play, rather than simply streaming it directly from the Dell.

But Microsoft Word documents stored on the Dell opened right up on the Mac. It was particularly impressive to be able to view a document or photo stored on the Dell from an iPhone thousands of miles away.

Dell Remote Access is a worthy service that’s worth a try.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.

Now, two more set-top boxes have been launched to try to marry the Internet and the TV. Both adapters, from Sony (SNE) and Roku, worked well in my tests, but each has limitations. The problem is that one of the boxes supplies content from a wide range of Internet video sources, but only works on selected models of one brand of TV set; the other works on a wide variety of TVs, but only provides a single source of content.

Sony’s adapter is the Bravia Internet Video Link. This is a $300 module that attaches to certain Sony HDTV models. It can either be set up beside the TV or snapped onto the back of the set. Once it’s connected to your TV and to your home network for Internet access, a new menu appears on the TV allowing you a choice of videos from numerous online sources, including YouTube, Yahoo (YHOO), Blip. TV, Sports Illustrated, AOL, Wired, and the Web sites of CBS (CBS), Showtime and more.

Setting up the Bravia Internet Video Link was straightforward, even though it involved a welter of cables. There is no built-in Wi-Fi — you need either a cable or an add-on wireless adapter to connect to the Internet. The primary hookup to the TV is via a modern type of cable called HDMI, for High Definition Multimedia Interface.

I tested the Sony Link using the company’s most unusual HDTV set — a tiny, very costly model that uses a very thin, very vivid new screen technology called OLED, for Organic Light-Emitting Diode. This TV provided a spectacular picture, but it isn’t required to use the Sony module. The Link works on many larger, more common Sony sets with more common screens. It just doesn’t work on non-Sony TV sets.

Sony’s Bravia Internet Video Link adapter

The Sony module doesn’t have its own remote control. It uses the one that came with the TV. This makes for an awkward experience, because there are no standard play and pause buttons, and various other buttons on the remote meant to do one thing on the TV may do another when watching Internet video via the Link module.

Also, I found some of the Internet content to be disappointing. Many of the items labeled “movies” on various Internet channels were really just trailers, and some content was stale. For instance, some baseball news videos on Yahoo were weeks old.

However, Sony plans to make one of its feature films, “Hancock,” available through the Link module before it’s released on DVD. More important, it will be adding access to Amazon’s (AMZN) forthcoming video-streaming service, which promises to contain a wealth of full-length content.

The Netflix Player by Roku is much simpler. In fact, it was the simplest set-top box I have ever tested. It costs just $100 and does just one thing: It allows Netflix (NFLX) subscribers to view its movies and TV shows via the Internet on a television set instead of on a computer. It can’t get you any other video content from the Internet.

The Netflix player is a small, plain black box that works with most TVs, not just digital or high-definition models. It connects using both old-fashioned cables, like the kind used by many VCRs and older DVD players, or an HDMI cable.

Unlike the Sony, the Roku box includes both wireless and wired Internet connectivity, and has its own remote. While the box is capable of displaying high-definition content, the Netflix service isn’t currently streaming movies and TV shows in high definition, so you get varying quality, depending on your TV and Internet speed, up to DVD-type levels.

There’s no added monthly fee required to use the Roku box, but you must be a Netflix subscriber. The box merely displays the movies or TV shows you have placed in your Instant Queue on Netflix. You have to do this on your computer before viewing the videos on the Roku box. You can choose from around 12,000 streaming movies and TV shows, far fewer than the 100,000 titles Netflix makes available via DVD, but a sizable collection.

In my tests, the Roku box set up quickly and easily, the interface and remote were simple and effective, and the movies and TV shows I tested streamed quickly and without hesitation over my fast home Internet connection.

Both products are meant to promote sales of other things — Sony TVs and the Netflix movie-rental service. They do these tasks well, but neither is the breakthrough solution that will connect most TVs to most Internet video content.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.