Are the mice still usable on other machines? What are the specs of your rig?
Just I have a feeling it has to do with the PSU delivering too much power, which could be over time frying the mice you attach, and who knows what to the internal components.
Specs atm are
Phenom II X4 b50 @ 3.4
Radeon HD 5570 1GB
Coolermaster GX 650w
Corsair Vengeance 4GB
And no the mice aren't usable on other machines