PC does weird

Hello everybody,

I have a problem with my pc. Sometimes my pc does very strange while it was working very well. What I mean, the icons at my taskmenu go to the left of my desktop, my start meny just doesnt open when I click on it, my rightmousebutton doesnt even work anymore and when I try to open a map, he doesnt open, I get a black page when I try to open, but other programs like IExplorer or games keep working. I tried a spyware scan (Adaware) and virusscan (Norton), but there isnt a problem. Does anybody have a suggestion or sollution? I can also put somes screens if I am not clear enough. Please help me, cause it is realy annoying!