Hi all, lately i have problems with my pc, sometimes the windows blocks/freeze and i must restart from the button; this happens like 1 time in 3 hours or 1 time in 7 days, it's random. The image freeze even if the pc is in idle, so i don't thing it's a stress problem.

2nd problem, the mouse cursor freeze for 2 sec(the image doesn't freeze, only the cursor), and after it's coming back to normal. I tried with several mouse's. I tried with another HDD and i have the same problem..

Pc config:

cpu: i5 750 2.66
gpu: msi gtx 460 hawk
mobo: asrock p55 pro/usb3.0
ram: Corsair 4GB DDR3 1333MHz CL9 XMS3 Dual Channel Kit
hdd: Samsung 250 GB SATA-II 7200RPM 16MB SpinPoint F1
psu: AntecBasiq Power 550W

I did reinstall the windows, update drivers and bios update, cleared cmos, tested the RAM with memtest86(no erros), check other video drivers.

lots of guys pointed that the mobo is the problem