Black screen while playing games

When I played video games such as Call of Duty 5, prince of Persia, tomb raider underworld freez my screen from time to time 1 or 2second then returned to the game.

I do not know what is causing the problem.

Thanks

Configue my pc:

Operating System : Windows Vista Home Premium Ed
Processor : Intel Core 2 Duo 45nm E8400 3Ghz
Graphics Cards : ATI HD4850 512MB PCIe 16x, Vo (ATX format)
Motherboard : Gigabyte GA-EP45-DS3R INTEL P45 ATX
Hard Disk : 320GB SATA II 16MB 7200
Memory : 2048 MB kingston 2x Dual c

I guess you have the power supply to the Sonata 3 like mine? that is to say, a 500W? If so the problem is not the Power supply . I would say more a problem with the Bios. tried to update it.

I have a ASUS motherboard so I do not know too much with the giga-byte. but trying to go to the manufacturer's site and download the latest BIOS.

There are 5 versions of the bios (F1 to F5) and the E8400 is supported from the very beginning, so I do not see why this would be the bios that would cause such a thing. Is Your graphics drivers are up to date? the problem did not appear after an update of these?