I'm new to the scope platform and have been reading alot of manuals lately

I have this strange problem I can't fix, when I use a midi keyboard, after a while XP stalls and I have to restart, same thing happens if I use my DDX3216 digi mixer to control Cubase, Just tryed it with Vsampler and same thing happened again..

Hope someone here have a solution to the problem..
I have a Pentium 3.0, abit motherboard, 1gb pc3200 ram dual mode. The computer is only used in the studio and only for music...TIA!