Massive frame drop issue in games.

So, I wasn't sure where to post this, and its also my first time posting on this forum.
As mentioned in the title the problem is that I get massive frame drops in games, wich sticks until I've restarted my computer.
The frame can drop from anywhere above 60 to well under 30, and this happens in all the games I have. I have also tried re-installing windows and that did not help.

My specs are;
GTX 590
i5 2500k
8gb "Vengeance" something ram
Some corsair power supply at 1000w
P67 extreme4 gen3
Running windows 7.


Any ideas are welcome, and thanks for reading!

 

I'll try it!