iMac 27 Inch Early 2009 freezes periodically
For the last couple of weeks my iMac has been freezing and requires a hard reset to fix. On at least one occasion the screen flashed before it froze.
Zahori, I'm having the same problem as well. I spoke with Apple Care over the phone, and ended up bringing it in to the Aple store to get it checked out. They kept it for about a week and ran diagnostics only to tel me that they could not detect any problems with the hardware. I thought maybe it could be a software related issue so I wiped the system clean, updated to Mountain Lion and the only major piece of software I have on now is Aperture which freezes so frequently its not even worth using. I assumed from the first time this happened that it had to do with the NVIDIA GeForce 130 but according to apple techs, it seems to be running fine.