Windows 7: Windows 7 problem with server boards?

Hi guys i had the following configuration of my workstation.

Intel 5520 2.26 ghz Xeon Quad Core ( 2 CPUS)
Intel 5520 SC
Hard Disk 150 gb Raptor Western Digital 10000 RPM
Hard Disk 1 TB Western Digital 7200 Rpm
Dvd Rw Sata HP
Graphics card Nvidia Quadro FX 1800
Intel Chasis SC 5300 + 600 watts Psu
8 gb ddr3 ECC ram (2 gb x 8 ).

yesterday i installed windows 7 and the problem starts. i play video and it stuck between playing my whole system stuck.
i don't know what to do. some time it plays but in 2 to 3 seconds it hang and then play and then hang and play my whole system is doing the same thing hang and play i don't no what to do. its totally shutting randomly.

then i check my processor performance meter and it 5.4 pretty bad with this kind of system. i check processor graph and it shows that my processor tacks load in 2 second and then release and tacks load in 3 or 5 or 1 second randomly it happens
i dont no whats wrong with my system or driver please tell me if somebody had face the same problem

Sorry For my ENG
Regards,
Sagar Sharma

Have you run Windows Update, updated your graphics etc?

Yes i have update every single driver of my system and update the windows also but still no result