I have had this computer for half a year now, and it has worked perfectly..... until now. I can start it up, but when I log in, it's almost like my mouse doesn't work. I can roll my mouse over something, and it highlights, but when I click, nothing happens. I roll over my taskbar and they dont highlight when ever you roll over them. I ran a virus check and it found nothing. 

Does anyone know what on earth is wrong with it? It was working fine 10 minutes ago :/