|I'm wondering if you've got some sort of EMI causing the problem. This would explain why a new wireless mouse is also having problems. When you tried it on your friends laptop, was it over at his house or was his laptop in the same vicinity as your desktop?|
Have you put any new electrical devices in your house. Anything like a device with an electric motor, desktop fan, air conditioning, flourescent lights, new TV, stereo, cable box, electronic device?
One more thought, what type of surface is your mouse on? Glass & plexiglass can cause problems with optical mice. Other surfaces can cause problems as well. Try different surfaces.