Mouse heats up and locks

I hope I can describe this problem correctly. I work in a small college and we have a lab with 30 PIII 500 Compaq deskpros with Intellipoint wheel mouses. During any given week I usually have about 2-5 machines that lock up. I get no keyboard response and no mouse response. Now to the strange point. On the locked up machines the mouse actually feels physically warm. After I do the dreaded power of/power on, the machine works fine and the mouse cools down. I wasn’t even aware that a mousecould heat up. Any help into what could be causing this, or suggestions to correct it would be greatly appreciated.