Grike, go into your Bitcoin Settings, Options, and limit coin generation to 1 processor (core). I have one box that will trip the overheat beeping after a short while of CPU+GPU mining unless I limit the CPU.
NO! You shouldn't even be using the generation option in the Bitcoin client
at all!
That miner is far far outdated. And if you really really really want to CPU mine against all better judgement, then you should be using one of the dedicated CPU miners.