BSOD ON BOOT, THEN REBOOTS

I put together a system for my 10 year old from hand me down parts of mine:
AS Rock P43Twins1600
E6600 cpu
400W PS
GT220
Raptor 10K rpm 300GB drive
Crucial DDR3
Win XP SP3

So put all this together and loaded Win XP 32bit SP2. Everything worked well, I downloaded all the latest drivers and updated to SP3. By the end of the week, he tells me it won't boot up on the first or more tries. When I looked at it, it starts to load, the a brief BSOD then reboot. 2 or 3 times in a row and maybe it will finally come to the screen that says windows did not load on the last attempt. If we get past this, it usually works, but a few times it did freeze while watching a you tube video. The BSOD is so fast, I can't possibly see what it says before a reboot.

At first there was 2 gb DDR2, so I swapped for new 4gb of DDR3, but with no help. Then a new power supply, but no change. New mouse & keyboard next, but no change.
I will guesss at hard drive next then video card, unless anybody has better ideas?