I have an Acer 5520 laptop. Often, when entering text, I find that the cursor has migrated to a different part of the screen for no reason, and I have to edit text to correct problems which occur for no reason. (I am not touching any other keys, nor am I leaning on the computer. My hands are above but not touching the machine.) Any ideas?

I have the same problem. I used to think that I wasn't touching anything also, but I learned that my problem is caused by my gently touching the touchpad. Sometimes I have to turn it off so I can type without having the cursor jump all over the place.