Some times when these sort of things happen it can be Java that wants to be running. Or sometimes there is a "highlighted" message that comes up below the Heading of IE and above the main Browser window which asks you to install an ActiveX element. I see you have reduced your Privacy settings to zero, so, again it can't be that that is the cause of the problem. Maybe someone else will come on with better knowledge than I have of IE!
Hi, following on from my link .. this could be as a result of 'tired' hardware, perhaps on the verge of a breakdown. Could be a CPU overheating problem, or a dying PSU. Could even just be dust and fluff inside pc with dirty fan blades or fans not running at proper speed.