Normal scans hadn't returned anything wrong with the computer, but it had still been running slower than it should so i decided to do a boot scan on it in case it could find anything. It never scanned and now is in a reboot loop, it can't start in safe mode, regular or the most recent working settings. I put in the XP install CD but i can't even get the option to boot from it or use the CD, it just goes through the same loop. I'm using Avast 5 Free on Windows XP. I have no idea what avast killed my system. Its currently turned off.