Second posting:
Just upgraded to new HD, installed XP home ed. At the
time I installed, I had a wireless (Microsoft Wireless
Multimedia keyboard) keyboard & mouse attached to the USB
hub. I use this wireless keyboard with my laptop but
decided to try it with the DELL 450mhz I'm upgrading.
Since I want to use the wireless hookup with my laptop
while networked to my desktop computer, I re-attached the
regular mouse and keyboard to the DELL. When I booted up, the
mouse and keyboard did not work at all. I rebooted in
safe mode... that didn't work. I rebooted and went into
CMOS but didn't really see anything to do. The mouse and
keyboard DID work when booting using the F8 key to the
screen where bootup choices can be made, so the problem
lies somewhere after XP is up and going. There have been no
error messages at anytime.

Is it possible that installing the new XP with the
wireless setup in use is keeping the OS from recognizing
a regular mouse/keyboard arrangement? Oh, I tried another
mouse and keyboard also... they did not work either!