Mac Pro :: Update / Replace Mouse Drivers?

I bought a Mac Pro last September, and I've had a run around of temperamental mighty mouse. Or so I thought. The one it came with I plugged in and it clicked like a mad demon, button 4 was basically useless as the slightest touch would trigger it. I had a Mighty Mouse that I owned before that I switched it out for, and the problem seemed to go away.

But it came back, and much worse this time. I unplugged the mouse to use it on my Macbook, and when I plugged it back into the MP the clicking went berserk again. This time I took it to the Apple Store to get it replaced. The genius plugged it into his Macbook at the desk, and it worked fine; no sporadic clicking at all. I assured him it did it like crazy and asked for a new mouse, which he replaced. He then threw out that it's probably not the physical mouse that's the problem, but rather the software in my Mac Pro. That kind of baffled me, but I had my new mouse and I was happy......................