For months I've been having problems with programs not responding, responding slowly, or freezing. When I open Windows Task Manager and select end task, it doesn't work. I want to run scans in safe mode, but when I press F8 on restart, I can't get it. I could previously get to safe mode before all the problems started. The only way I can get out of a program not responding or freezing is to hit the off button, not through shut down/restart. I'm having to do this constantly now. I suspect the computer has a virus or problems with spyware/malware. Bitdefender quarantines lots of temp files, which I delete. Hitman Pro finds tracking cookies, which I delete. Malwarebytes never finds anything. I need help in determining what problem my computer has and how I can fix it.