My Phenom II x4 965 BE is over heating, why?

[r160bn]

My usual idle temps for my CPU is supposed to be at around 50 degrees Celsius but now it's at 75, which is hotter when I have it on full load. I started noticing this yesterday. I've had cleared the dust in my computer and checked if the fans were spinning but still it stays at 75. Can anyone help me?

Spoiler

 

[socialfox]

You could re-apply thermal paste, anyways did you clean the dust out of the heatsink as well? That is kind of hard to reach compared to cleaning up the fan. Also this is the stock cooler right?

 

[r160bn]

Yes I've had clean the dust out of the heat sink and yes it is a stock cooler.

 

[socialfox]

Hmm...is the stock cooler loose? Also re-consider the thermal paste. How long ago was it between the 50 degrees of load and 75 degrees. You can also try lowering the voltage of the processor if this is stock clocks.

 

[r160bn]

Ok, so i notice something really weird. I can stop the over heating once I open task manager and goes down to 45 degrees Celsius, but when I close task manager it heats back up to the 70s. Anyone know why this is happening?

 

[socialfox]

Interesting...do a virus scan. Describe what you are doing when its at 70 degrees.