ACER laptop that just stops

Hello,
I have an ACER laptop that won't start now. Originally I started having problems with it just stopping while running. It seemed to stop when I opened videos and run anything that was a video. It just stopped. I could get it to reboot and run as long as it wasn't asked to run a video. Then it got worse, alot of graphics seemed to make it stop. It has now got to the point where it just won't even boot up without quitting. Could it be a processor problem? If so, is it as easy as buying a new processor and changing it out with the old to get it revived? Are those symptoms of a processor, hard drive, virus, etc? I have McAfee on the laptop so I thought I should be ok from a virus standpoint.