When you connect to a PC using direct dial or virtual private networking (VPN), you're simply joining the host's network from far away. When you try to open a Word document that's actually sitting on the distant PC, your laptop's copy of Word opens and loads the file. Your laptop is doing the actual word processing; the host just sends and receives files as needed.

Vista's Remote Desktop feature is a different animal. In this case, you're using your laptop to control the host computer. If you double-click that Word file on the host computer, you open the copy of Word on the host computer. All of the word processing takes place on the distant machine; all that passes over the connection between the two computers is a series of keystrokes, mouse movements, and screen displays. The host is doing all the work. Your laptop is just peeking at the results.

Once you understand the differences between these technologies, you can make a more informed decision about which to use when. For example, suppose your PC at the office has a folder containing 100 megabytes of images you need to incorporate into a PowerPoint document. Using a remote networking connection means that you'll have to wait for the files to be transmitted to your laptop before you can begin workingand if you've connected to the office machine using a dial-up modem, you'll be waiting, literally, for several days.

If you use a Remote Desktop connection, on the other hand, the files remain right where they are: on the host computer, which does all the processing. You see on your screen exactly what you would see if you were sitting at the office. When you drag and drop one of those images into your PowerPoint document, all the action is taking place on the PC at the other end.

Of course, if the computer doing the dialing is a brand-new Pentium 7 zillion-megahertz screamer, and the host system is a 5-year-old rustbucket on its last legs, you might actually prefer a remote network connection, so the faster machine can do most of the heavy work.