[SOLVED] RAM sticks only work in 4th slot

[spiralhun]

I just installed a new CPU cooler, and whenever there is a stick of ram in any of the first 3 slots the pc does not boot.
If only 1 stick is installed and that stick is in the 4th slot everything works perfectly.
A few hours ago i was using the 2nd and 4th slot and had no problems.

What causes this and how can I fix it?

 

[spiralhun]

FIX:
the screws on the cooler were too tight, I had to loosen them a bit and now everything seems to be working.