Chances are your mouse (optical) is sitting on a pretty shinny surface. That surface is what is causing the mouse to every so slowly inch up on your screen. Quite a common problem.
To prove this place your mouse on a piece of A4 or letter size paper and see if the problem persists. I'm certain that it wont (unless your mouse is faulty). You may want to find a mouse pad with a flat (ie) non shinny surface to use.
Cheers
I left my Mac idle and went to look at the screen and noticed the cursor slowly moving up the screen- it looked like it was struggling to go up, so I w anted and it eventually went to the stop and stalled. I have a mouse with a sensor on the bottom laying on a flat surface on the mouse pad. I have my fire wall on and no sharing. This concerns me as it amkes me think that someone had remotely accessed my computer. Also, Airport and Blue Tooth are disconnected

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