I'm sorry but I didn't see where to put this problem, so I put it here.
I had a Microsoft SideWinder gaming mouse that kept scrolling up and down all by itself. Sometimes it would just move a little and other times it would go crazy. I was running Windows XP at the time (3 days ago I changed to Windows 7.) The problem was so annoying that I bought another mouse, a Logitech G500. It has the same problem!! The mouse is straight out of the box! I installed the ScrollPoint software and set the speed of the scroll wheel hoping that would help; it didn't. I went to the Device Manager to see if there was something conflicting and there wasn't. Like I mentioned before: I just installed Windows 7 3 days ago, so had to format the HD.
Since this has happened with 2 different mice on 2 different operating systems I am stumped! This is a wired mouse, so it isn't interference from something else. The wheel isn't dirty as I just got the mouse today. Please someone help me? This is super annoying!
There definitely seems to be something going on with your computer. It could be the motherboard, or it could be the cables that connect them to the motherboard. Though the ones on the back are likely directly connected to the motherboard.