BSOD while playing games or randomly

Andrew131

Honorable
Jun 21, 2013
40
0
10,530
So after installing Portal 2 I had my first BSOD on my PC its pretty new not even a year old. Now it crashes if I open a game or if not then my pc will crash after some time being on. I've formatted the PC ran memtest86, chkdsk on my hard drive, scanned for viruses but nothing. Do you guys know what may the problem be?
My PC specs are these:

AMD A8-6600K @ 3.9 Ghz
Sapphire HD 1 GB
8 GBs of Ram
Windows 7 64 Bit
and a 650 Watt PSU (not really high I know)