I was downloading and trying out various programs today and in the process really messed up XP. My computer got really unstable and would not go beyond the logon screen in XP. I gave it a few tries and finally was able to go to System Restore and I was able to roll back to my previous settings. What tools do you guys use to either prevent this from happening or to solve the problem. System Restore is no use if I'm not even able to boot XP. Any boot disks that you can recommend??