Have XP Home, Screens freeze up, or wont allow me to scroll down. Programs stop responding, Portions of old screen will still show up on new screen opened. Sections of screen 'jitter'. Dont use System Restore. Regularily (daily) do Disk Cleanup and Defrag. When try to run Avast Antivirus it takes forever to run, way longer than it used to and and now it freezes. Had to run CCleaner twice before I could get it to work. Did all the 8 steps, Avast worked fine, no viruses or problems found, next day, it is back to hardly working. ??? Any ideas. A while ago had a trojan in Mozilla (also use Thunderbird) in Application Data - User Profile. I removed Mozilla and manually deleted the User Profile files. Did that do the trick?? Or is the trojan somehow still there?? Am under the impression Avast has antispyware protection, am I wrong here?? If so, what do you recommend?? Any other ideas, appreciate any help here, really dont know what I am doing.... Cheers, Emma