computer freezing when mining

When I first installed my two 5830 cards I had no problems mining but now my computer freezes when starting the mining program (I am using DiabloMiner). After the first few days of mining for some reason I had to connect to the bottom card to start my mining but now that dosent work anymore. I was getting internal error: compilation failed and it was suggested to update the drivers to try to fix and that worked but then I rolled them back to get better fps on bad company 2. I had only rolled them back from 11.5 to 11.2 (I was originally using 10.10) and again I got the internal error: compilation failed so I updated again to 11.5 and now my computer freezes when trying to mine. My problems started when I removed the plastic cover from the bottom video card trying to get lower temps from the card, I had already put a aftermarket cooler on the top card and had no problems from that.