Why my pc is restarting when i play some games in high performance?

[sakis]

I have

INTEL CORE 2 QUAD CORE Q9550 2.83 GHZ LGA775 - 1333 FSB - BOX
LG W2452T – PF 24'' TFT WIDE FULL HD 1920x1200x32 60Hz
WESTERN DIGITAL WD5000AAKS 500GB SATA2
WESTERN DIGITAL WD5000AAKS 500GB SATA2
WESTERN DIGITAL WD5000AAKS 500GB SATA2
KINGSTONE 4GB 1066 MHz (4X1GB) DDR3 SDRAM 1333MHZ
ASUS HD4890/HTDI 1GB GV-R489-1GH-B GDDR5 PCI-E RETAIL
GIGABYTE 6-QUAD ULTRA DURABLE 2 X38T-DQ6
X-Fi xtreme gamer
Dual Gigabit LAN: Realtek RTL8111B PCIe Gigabit Ethernet
THERMALTAKE FULL TOWER BLACK VA8000BWS
TRUST 570 DUAL FUN PW-5500
LOGITECH G15
NEXT 7.1-CHANNEL SOUND SYSTEM
SONY NEC OPTIARC SATA 2 LIGHTSCRIBE DUAL LAYER
Microsoft Windows Vista SP2 x64 Greek

and when i play some games like colin mcray dirt in high performance my pc restarts why?

 

[shubham1401]

Check the temps of your hardwares.
Download HWmonitor-a free tool to monitor temps and post them here.
It may be overheat problem.

 

[xaira]

^+1