Can't figure out PC freezing

gustafangus

Honorable
Jan 20, 2013
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This is my 2nd post, because things just got TOO complicated. Anyway back in november, I build a PC for a friend. these are the parts:

FX 8320
ASUS M5A97 EVO R2.0
R9 280X
XFX 550W CORE PRO
Ballistix Sport 8gb 1333mhz
WD Blue 1TB

The thing kept freezing since the first days. Just doing anything, it would freeze. Thing is, if there is no internet connection, it works very well. He can play any offline game for hours without freezing, but then if there is internet, it freezes. We've tried 2x different WIN7 CDs, and windows 8.1. Always the same problem. Things we've tried:

1. RMA the hard disk (before freezing, the HDD light acts weird, and keeps flashing less and less until it goes off completely. Does that on both HDDs.)
2. Multiple reinstallations of OS. (like stated before)
3. Bought a 7€ ethernet card, connected it, still freezes.
4. Memtest, ran for like 12 hours very well, no problems.

Thing is, my friend opened a program, which i'll tell later, because he forgot the name, but it said the motherboard is unknown, so it's the motherboard, right?

Thanks, any other info, i'll gladly tell!

thanks in advance!