I don't know if it is a bug, but my floppy drive turns on when CCleaner runs. When CCleaner finishes, it turns off. I know I don't really need a floppy drive, but still...

If you've accessed or even scanned a floppy disk in the past few days it's something I suppose a bug in WinXP that causes it because launching other programs such as WinRAR, antivirus, etc., causes it to happen on my system although I've seen it happen on multiple systems.