Asus mobo problems...

I upgraded my PC to a A7V600 mb and a AMD XP 2200+. The PC does not boot up
properly, a few seconds after hitting the power switch you can hear the CPU
fan dying for a few seconds, then it picks up again. When I go into BIOS it
freezes up after a while. And when I actually get past booting and trying to
install OS, it freezes up as it is trying to copy the install files. I am
running a Crucial 256M DDR PC2100 memory stick, it has been working ok in my
other PC. a Enlight 420W PSU, a brand new 80Gb Seagate HDD. Basically only
thing I haven't tried to swap out yet is the memory stick. Can it cause
these type of problems even if it works ok in my other PC, a A7A266 with
Athlon 1.2. Please help me, getting frustrated....

Michelle