I don’t know whether this is a hardware or software issue.
My wife has a Toshiba netbook (don’t laugh) running Windows 7. When on a menu or a webpage, it will suddenly jump to something else. It seems as though just hovering over an item or link without selecting it will activate it.
She uses the pointing device on the netbook, not a mouse. Does this have to do with the pointing device or is it perhaps a feature of Windows 7, with which I am unfamiliar?