irql_not_less_or_equal in vista

Greetings!



I have problem with my computer that randomly crashes on Vista ultimate 64bit.

Sometimes i can work whole day without the problem, sometimes it crashes after 5min of work.

I have checked my Ram and Hard drives for errors, bought new motherboard.



When it crashes it shows the irql_not_less_or_equal error.

I tried looking into crash dump file, but dont really know where to look for cause of problem.



This are my sistem specs-



CPU - Q6600 @2.4Ghz

MBO - Asus P5q Pro Turbo

Ram - Ocz Xtc 2x2gb @800Mhz

GPU - Sapphire Radeon 4870 1gb Black

HDD - Seagate 250gb, Seagate 500gb, WD 640Gb

Soundcard - Creative Platinum X-Fi

Mouse and Keyboard - Logitech MX518 & G15

Power supply - Corsair 620



Thx in advance for help!

"When it crashes it shows the irql_not_less_or_equal error"Leading causes

Leading causes are:
Drivers (Obsolete, buggy, or corrupt)
Hardware--
RAM, MBD Ram settings, Poor cooling (CPU, Video GPU, MBD chipset)
Power Supply  a 620 w PS may be a bit small if the failures occur during
heavy 3d use.
(All power supplies are NOT equal!)
Overclocking

I have a system with an ATI Diamondmm HD 4890, Phenom II 955, and 4G OCZ
Ram, 2HDD, & DVD burner
The PS is a "true" 910 W single buss supply with about 80-90% efficiency
Max draw is around 580-600w in 3d games, according to the UPS. The CPU & GPU
can reach ~55deg C, with "stock"
heatsink fans and more than adequate airflow in the case. A bit of custom
baffling can reduce temps by a deg. C or so.
(5 case fans, One top, two lower front, one upper rear, one (180mm) side),
plus the usual PS internal and CPU& GPU fans
Creative Labs Drivers and Logitech drivers are also possible suspects, based
upon past reputation.

When you say random, is any particular task or app software in use at the
time of failure?

http://support.microsoft.com/kb/818501

http://support.microsoft.com/kb/818501

Soundcard - Creative Platinum X-Fi is a likely culprit!

Soundcard - Creative Platinum X-Fi  is a likely culprit! See if new drivers
are available.