Windows XP Pro: The Missing Manual

Conversely, if you just love Windows XP and never want to go back, you may prefer to reclaim the hundreds of megabytes of disk space that your old copy of Windows 98, 98 SE, or Me is taking up.

Here, too, there's not much to it. Choose Start All Programs Accessories System Tools Disk Cleanup. As shown in Figure A-6 at bottom, the Disk Cleanup program lists a lot of stuff that you can permanently delete ”and in the list, you'll see the name of your original Windows version ("Windows 98/Me Installation Files," for example).

Just turn on the checkbox and then click OK. The 600 megabytes you save could be your own.