PC won't power down on shutdown

Recently my PSU decided to die and refused to turn on. I have since replaced it but am experiencing problems at shutdown. The monitor and hard drive power down as usal however the CPU fan and case fans continue to spin. When I reinstalled windows (before gfx drivers were installed) I noticed the computer whould freeze at the shoutdown screen and after the drivers were installed would repeat the first problem I mentioned. I have since been changing the parts I can and have experienced the same problem with a different graphics card and hard drive. This leads me to believe it could be a mobo problem?

Specs are:
AsRock b75M
i5 3550
Gainward GTX 570
WD Caviar Black 640GB
Silverstone Strider Plus 750W
8GB GSKill Ripjaws @ 1600Mhz
All the parts with the exception of the hard drive are 2 weeks or less old. The PSU was purchased after the inital one failed.

I have ran Memtest86 for 4 hours with no errors and Prime95 for 3 with no errors. The computer runs fine as far as I can tell until shutdown. Any advice on what my next move should be is appreciated.

Cheers,

Pinnacle
 
Back