I'm having trouble defragmenting my computer. When I start it up it works fine, but then a message appears that says "Drive has changed", followed by "Not enough space on this hard drive to defragment this drive", which is absolute nonsense since there's only 20% usage on the drive. I'm running Windows 98. Please help!

Windows is notoriously sticky when it comes to the defragmentation process. Not only does it take forever, but nothing else must interfere with it, which seems to be what's upsetting your computer's disposition.

When I say nothing, I truly mean that no other program must run in the foreground, background, internally, externally, upstairs or downstairs — nothing.

So reboot your computer and then close all programs that start up automatically — i.e. those in the system tray (the bunch of icons on the right-hand side of your Windows toolbar.

Systematically right-click on every icon and if there is an option that resembles stop, exit, shoot, or kill, then select it. Also make sure that you don't have any screensavers or monitor energy saving functions waiting in the wings to activate mid-defragmentation.

When you're sure your computer is sitting dumb as a baked turkey on Thanksgiving, then start up your defragmentation again. She should be turning over quite nicely this time around.