System starts, but wont boot up.

i've been getting these errors while shutting my pc down for a while, and now my pc wont boot. i've been getting this error:


"DRIVER_IRQL_LESS_OR_EQUAL"

stop: 0x000000D1, 0x00000008, 0x00000008,0x00000000, 0xBA6D0986

*** si3132r5.sys address BA6D0986 base at BA6CD000 date stamp 443D27A2

along with another "memory dump" error.

both gave me blue screens.

i kept getting errors when shutting down and then it would take me wo tries to turn on my pc. meaning i would turn it on and let it start to boot and idle. nothing boots to te screen though; the system is just on. and then i would power off with the main power button and restart the pc. once i did that, my pc would boot up just fine.

now when i go to turn on my system, it turns on and the all the lights turn on. even my boot up screen for bios tries to pop up onto the monitor, but quickly turns blank. after that, the system stays on but nothing shows up on my monitor. my monitor light is green, meaning that it is on. i dont get any random or series of beeps. i only get a few clicking sounds.(sounds like my HD). i'm not sure if i have my two HD's set to the rights settings in Raid 0 or if something went wrong. i cant run any tests because my pc wont boot anymore. i tried using only 1 ram at a time to see if one of the ram's went bad, but that still failed. no overclocking. i've had this system for less than a year.

is this a HD, RAM, or GPU failure?

Main Features:

Asus P5N32-SLI Premium
Intel C2D 6600
2 x WD HD 74GB 10,000RPM Raid 0
EVGA 7950 GX2
OCZ 700w PS
Windows XP Home

please help.