KT7A-Raid problem

I have a KT7A-Raid board, with a 1 GHz Athlon processor and 768 MB
PC-133 RAM, running Win 98SE. I have run this board configured with
Raid-0, but I'm now just using it without the Raid function.... but I
do have 4 WD drives on it. The system has just recently started having
a problem with locking up. It usually occurs when I'm doing something
important, like editing a large Photoshop file, or have several apps
open at the same time. On lockup, which also seems to occur with a
mouse click (using a MS Intellimouse USB), a hard reset is required,
as there is no response to either the keyboard or the mouse.

Does this sound like its processor or Motherboard related? Are there
system setting that I could adjust (perhaps trying to slow down
things) that I could try that might improve stability? Could it be
related to the mouse? (I've swapped out the one I had been using for
another of the same model, with no improvement).

Appreciate any suggestions.... I'd like to keep this system running
for at least a few more months before upgrading to a newer
motherboard.

Charlie Hoffpauir
http://freepages.genealogy.rootsweb.com/~charlieh/