QHow can I tell what programs I need to keep on my machine and which ones I ought to dump?

AIf you think your computer has a few stray applications running amok, your first moves should be to run anti-virus software, using the latest virus definitions, and an anti-spyware utility such as AdAware (www.lavasoftusa.com).

Next, you should check to see what's running in background on your PC. Type "msconfig" at the Start Menu's "Run" command to see a list of everything that loads at start-up. If you don't recognize the applications, have Windows search your hard drive for files matching the names. When it presents its list of search results, look to see what directory contains the programs.

If the name of the directory isn't identifiable, you might have a problem. Go to www.spychecker.com or www.annoyances.org to see if it is listed as spyware. If it is, you shouldn't let the program run.

Utilities such as Ace Utilities (Windows 98 or newer, $15 at www.acelogix.com) and StartMan (Windows 95 or newer, free at www.forrestandassociates.co.uk/pcforrest/startman_v1.html) make it easier to stop programs from loading at start-up.

I just installed Tiny Personal Firewall and have been inundated with networking jargon. For instance, what's an echo request?

An "echo request" is more often called a "ping." It's a simple "Are you there?" message sent to another computer on the Internet, which requires only a "Yes, I am" reply from the target machine.

In your example, the ping the firewall detected is most likely an attempt to see if your computer is open for an intrusion attempt -- which your firewall should stop.

-- John Gilroy

John Gilroy of Item Inc. is heard on WAMU's "The Computer Guys" at noon 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 or via e-mail to jgilroy@iteminc.com.