I think this might be the weirdest thing I've ever seen a computer do. It's a Windows 7 SP1 machine. When I position the arrow in the middle portion of the screen, nothing I do with the mouse, except moving, has any effect. It means that if a small dialog box pops up, in the middle of the screen, as it does, I can only communicate with it with the keyboard. What could be the cause, and what do I do to make it go away?
Update: Here are the promts mentioned in the comments. They have no business being there.
First the first two pop up, right after system start. The other two pop up after the antivirus downloads the updates. The ones on the right come up on top of the ones on the left. I've dragged them using the keyboard (the mouse won't work there). The ones on the left are unresponsive. When I turn the first ones off, the problem persists. I believe the problem was gone when the second ones popped up or when I turned them off.
Update: Removing Avira removed the problem, but unfortunately installing it again makes it come back. I'll add the avira tag.