Toshiba Satellite problem

Hey, all,

I'm back with a problem that I hope is curable, but I fear the worst. I was
given a Satellite A45-S250 by a family member. It intermittently booted up
but didn't run for long. It had the problem of BSD after memory dump on a
regular basis. I looked up the error message and many suggested bad RAM. I
replaced the RAM with known good RAM and the problem persisted. I disabled
all the peripherals I could and tried to load a fresh install of XP. This
didn't work. Long story, short: I thought I might have a burnt CPU so I
took out the P4-2.8 Celeron that runs at 533 and replaced with a P4 M 1.6
that runs at 400. According to the Toshiba website the mobo should run
either. I tried booting the laptop with the 1.6 and it wouldn't boot. So I
replaced the 1.6 with the original 2.8 and now the laptop won't boot at all
with the 2.8. It does not go into the BIOS even though the lights come on
and I hear activity in the cd-rom. I fear that I might have blown the
motherboard.

Anyway, if anyone has suggestions as to what I might do at this point beyond
getting a new mobo I'd like to hear them. Again, thanks to any and all who
take the time to suggest possibilities. JG