Freaky reboot/crash problem

[slackerinabox]

Hey guys,
My pc recently started having weird reboot problems... The system would just reboot without any warning - no blue screen of death, no freezing, etc. I would just be typing and -bam- back to the memory check screen.. I was overclocking a bit so I then lowered my overclock back to stock speeds and the problem continued to the point where my system wouldn't boot into windows...I reinstalled everything and the system seemed to work fine - until now.. After 4 random reboots I'm stuck right after the bios checks the IDE devices (doesn't even get to the "WINDOWS IS STARTING" screen).. Any ideas what could be going on? Below are my specs:

Abit BH7
Intel p4 2.4b with stock cooling (running at 2.4)
512 mb pc3200 ddr ram (running at defaults)
2x40 gb 7200 rpm western digital hard drivers raided on a Silicon Image raid controller (used for downloads and swap file)
80 gb samsung on primary master hd (system / applications disk)
pioneer a04 dvd-r on primary slave
400 watt power supply ( i think sparkle... not exactly sure)
geforce 3 ti-200 (FIC i believe)
Soundblaster Audigy sound card

Running windows xp pro with all the latest updates....

Any pointers would be very appreciated.. My cpu hovers around the 52 degree point most of the time - I don't think this is a CPU or system cooling issue (have an extra case fan).. typing this on my mac cause my pc's currently resting

 

[mechBgon]

What happens if you unplug all the drives from both power and data cables, except your primary drive? And is there a chance your primary drive is dying, perhaps?

 

[slackerinabox]

Well, my primary drive(s) used to be the raid 0 stripe set (two western digitals) but I reversed the combination after it crashed on me the first time.. Still has the same issue.. I will try just running the one drive if you think that would help

 

[slackerinabox]

ok- so I'm going to simplify my life a bit.. Going to ditch the raid controller, run one of the 40gb's as a system disk and the other drives as "dump" drives... Maybe the raid card is at fault (I mean, I paid $15 for it).. Maybe it's not.. we'll see

 

[slackerinabox]

OK.. Done (well, reinstalling windows).. While I wait for this to crash again (or not) does anyone have any pointers? Could this be a virus? I'll find Norton and give it a whirl.. Could it be an overheating hd? any ideas?