QI stupidly installed a spam-blocking program advertised in a pop-up ad and immediately reconsidered. But even after following the uninstall directions, the application is still there. Now its developer wants to investigate by remotely accessing my computer. This makes me very uncomfortable.

AYour wariness is well-founded. Rather than let a company like that snoop around your computer using Windows XP's "Remote Assistance" feature, try a different XP option called System Restore.

Go to the Start Menu, select All Programs, scroll up to Accessories, and then select the System Tools submenu to run this utility. Pick a restore point that predates this program's arrival and let Windows take your computer back to the state it was in at that time.

The downside of this Wayback Machine-type software is that it will also blow away any programs installed after the unwanted application -- but you won't lose any data, and you can always reinstall the programs you do want.

(This reader wrote back: "Your suggestion worked beautifully.")

Apple's iPod site indicates a system requirement for Windows 2000 or XP. My computer runs only Windows ME. Can I still use an iPod? If it helps, I don't really care about downloading music.

Yes -- Apple's iTunes program, bundled with each iPod, does require Win 2000 or XP, but you can also use a third-party program to move songs to an iPod. Try ephPod (www.ephpod.com) or XPlay (www.mediafour.com).

My five-year old mouse has gotten somewhat jumpy -- control of the arrow is not as good as it once was. Would a new mouse take care of the problem?

If cleaning out the rollers on the inside doesn't work, go ahead and buy a new optical mouse. That should definitely fix the problem -- and you won't have to clean out its insides every month either.

-- Rob Pegoraro

Rob Pegoraro attempts to untangle computing conundrums and errant electronics each week. Send questions to The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or rob@twp.com.