Ok here is the problem i play some games and i get randomly black screen and computer freeze. So i restart pc and i get one long beep and one short beep i restart again and same thing. Then i turn off pc buy pressing power button and turn on pc again and works.
Amd athlon 64 x2 4800+
3gb ram ddr2 800
Lc power 550W lc6550 good german quality psu
Windows 8 Pro