I had a problem with my graphics card overheating after gaming for a while.
So I put a stationary fan, which we had in the living room during summers, to blow air straight into the box.
This was good as it wouldn't strain my 300W power supply, as connecting a PC-fan might.
Anyways the cooling worked, thus I installed 2 new fans, a 400W power supply and it's been working ever since.
k: