Q: I have a Pentium 166 desktop computer, and I want to add a Diamond Viper 770 AGP video card to it. Is that new card too advanced for this tired old chip?

A: Hey--watch those remarks about tired and old; I am much older than the Pentium 166 and feel quite perky.

If you own a Pentium 166 computer, you can get a lot of bang for the buck with a memory upgrade, a hard-drive upgrade or even a faster external modem. But the logic stops with the AGP video upgrade.

Video for Intel-based computers evolved from ISA (industry standard architecture) slots to PCI (peripheral component interconnect) slots to the current AGP (accelerated graphics port). As a general rule, the Pentium 166-class machines were made with PCI slots. So if you bought the Diamond Viper 770 graphics card, you would have no place to plug it in.

In this case, I would recommend the Diamond Viper V550 ($129), a PCI card that will make the video scream.

Q: What do you think of those inexpensive personal computers?

A: One word: "disposable." These bargain-basement personal computers may be fine for light-duty applications, but you'll curse the things six months from now when you find out you cannot upgrade them.

Most of the bargain machines come with 145-watt power supplies. If you choose to add an internal Zip drive and a CD-R drive, you may discover your system is overheating. This usually means you need to upgrade the power supply, to 250 watts.

Or let's say you buy a new video card and install it but find out that the good guys don't kill the bad guys any faster in your video games. Your system may not recognize the new video card. Many of the less expensive systems come with the video as a part of the motherboard. Some will automatically detect the new card, but some won't. You may have to make a change in the system menu or read the manual to find out if a jumper change is needed to make the new video card work.

Finally, these systems usually come with a modem classified as a "winmodem." They save money on hardware by having the operating system do some of the work. The net result is a finicky modem.

Q: Recent articles have said that using a cable modem for Internet access opens your system to hackers. Should I just consider DSL?

A: The bottom line here is quite simple: It doesn't matter how you connect to the Internet--telephone modem, cable modem, DSL or T-1 line. If you allow file sharing, you open yourself up for trouble. Basically, file sharing means that you're instructing your operating system to let outsiders look at files on your computer.

So go to "my computer" in Windows, right-click on "C," left-click on "properties," then select "not shared."

Consumers who want high-speed Internet access normally compare cable-modem service and some variation of DSL (digital subscriber line) service. They are available for widely differing prices in many parts of the country.

For example, where I live in Fairfax County you can subscribe to a cable-modem service for $49.99 per month. This will give you speed of up to 1.5 megabits per second on downloads and 192K on uploads. One DSL service that's available would cost $49.95 per month for 640K download and 90K upload. Many other DSL configurations are available.

You have to buy a special modem for digital subscriber line service. Martha Stewart recommends fresh fruit in season; I recommend a cable modem if you can get it, because of its greater speed. Remember that cable modems are normally available only in residential areas. If you are a small business, you may need to investigate DSL service.

John Gilroy of Item Inc. is heard on WAMU-FM radio's "The Computer Guys" at 1 p.m. on the first Tuesday of the month. Send your questions to him in care of The Washington Post, 1150 15th St. NW, Washington, D.C. 20071-5302 or via e-mail at jgilroy@iteminc.com.