I agree with finncapt. Updating your BIOS is, in my view, the last thing to try. Get it wrong in any way and you motherboard is useless.
Slowing and freezing seem to point to overheating. I would start with a good clean up inside especially the fan and then re-seat the heat sink with some good quality paste. And don't have it next to a radiator!
If that does not cure the problem, then look for other causes (RAM, etc). You could also change the mouse battery if it is wireless.