PC freeze after few minutes playing PR

[doougl4s]

Hello people,

I'm creating this topic because it is my last option. I do not know what happens on my computer now, I play PR for over 5 years with the same computer.

When I'm playing, I can not stay more than 10 minutes in the match, because my computer freezes. I can not press ctrl + alt + del, alt + tab, nothing. Neither the restart button on the pc tower works. Is there any light at the end of the tunnel?

Windows 7 Ultimate x64
i3-530 2.9GHz
12GB RAM DDR3
XFX ATI HD5770 1GB 128bits [Driver 12.10]

This bug only happens in PR, I have several other games heavier and never happened.
Sry for my bad 'google translator' english