My work computer has been running very slowly for awhile. It used to be half way decent but something got a hold of it and it's insane now when I'm on the internet. I've done all I know to do. It's windows xp and I have AVG antivirus, used CCleaner, defraged... I even took it to a computer tech. He couldn't find anything but changed my internet browser to firefox. It helped slightly but it didn't click with some programs that I have to use so I switched it back to windows internet explorer. I'm not very computer savvy but any help you could suggest would be greatly appreciated.