My machine has started to exhibit some odd behaviour it is an AMD 2000XP chip and runs Windows XP with Service Pack 1 and updates, I have not installed SP2 yet. The DVD-RW drive apears not to read any Discs (tis has happened once before and a restore got it working again). I then went to restore and all my previous restore points have gone? Also when running Norton Antivirus a message appears unable to run check due to critical error. I have tried deleting the drive from the system and letting it find it again , but no good. Any Suggestions?