Random Restart?

Hello,
My current issue consists of playing Combat Arms and my pc restarts randomly.
Sometimes it takes 15mins sometimes it's 1hour .

Any suggestions?

CASE - XCLIO A380PLUS

MOBO - Asus M3A78-CM
CPU - AMD phenom II X4 955
RAM - OCZ Fatal1ty DDR2 4gb 2x2gb sticks 800mhz
V-Card - XFX XXX 5770 1gb 1300mhz / 875mhz
HDD - WD 500gb 32mb Os on here
OS - WIN 7 ULTIMATE
Storage - WD 320gb 16mb
PSU - ETASIS 750watts


Hmm CPUID HW Monitor Specs


Hardware monitor ITE IT87
Voltage 0 1.01 Volts [0x3F] (CPU VCORE)
Voltage 2 3.36 Volts [0xD2] ( 3.3V)
Voltage 3 3.44 Volts [0x80] ( 5V)
Voltage 4 12.67 Volts [0xC6] ( 12V)
Voltage 5 -6.34 Volts [0x63] (-12V)
Voltage 6 -8.19 Volts [0x80] (-5V)
Voltage 8 3.28 Volts [0xCD] (VBAT)
Temperature 0 37°C (98°F) [0x25] (TMPIN0)
Temperature 1 40°C (103°F) [0x28] (TMPIN1)
Fan 0 1912 RPM [0x161] (FANIN0)


Hardware monitor AMD Phenom II X4 955
Temperature 0 35°C (95°F) [0x11A] (Core #0)
Temperature 1 35°C (95°F) [0x11A] (Core #1)
Temperature 2 35°C (95°F) [0x11A] (Core #2)
Temperature 3 35°C (95°F) [0x119] (Core #3)

Hardware monitor ATI Radeon HD 5700 Series
Temperature 0 48°C (117°F) (GPU Core)

Hardware monitor WDC WD3200AAKS-00L6A0
Temperature 0 38°C (100°F) [0x26] (Assembly)

Hardware monitor WDC WD5001AALS-00J7B1
Temperature 0 38°C (100°F) [0x26] (Assembly)