I tried to regvac (501-25) scan my WinXP -SP3 computer and today, (expert mode) and during the scan the computer just reboots! It happened every time I tried it. Nothing has been added recently to the computer. If I use the Novice mode, it completes the scan normally.  Any suggestions on trying to troubleshoot what the expert scan is triggering to cause the computer to reboot?  I have had no reboots in normal use with other programs, or in Regvac on this computer before, so I'm thinking something in the registry doesn't want to be scanned. My viruscanner (Avira) is up to date as is all the MS WinXP patches.

   I have never heard of that.  I do not know why it would reboot.
   I guess the first step is to find out exactly where in the scan process, it is rebooting.  You can try manually running the individual tools in the Expert zone that your scan is running to find this out.

The reboot is caused by my selection of automatically restart in case of system failure in the System Properties Advanced Menu. If I shut off the auto restart, I get a BSOD with a message of PAGE FAULT IN NON-PAGED AREA.

THe system failure occurs during the Bad Link Cleaner operation (even in Scan ONLY SAFE Locations!)

I've tried msconfig.exe minimal booting (diagnostic setup with basic devices and services only), and it still crashes during Bad Link Scanning.

FWIW, I also use JV16 Powertools 2009 (v1.90-540), and the system reboots during both quick system analysis and during registry cleaner scanning, like RegVac scanning. Because of the way JV16 is set up, I haven't been able to localize where in the scanning process the crash occurs, except that it is about midway though the scanning modules.

I meant to add that I tried MS Eventvwr to see if any insight into what was occuring at the time of system failure, and came up empty handed. I read error ID of (in order 7025, 7036, 7035, 7036,....6009, 6005.

7035-36 as I found from MS website,(http://go.microsoft.com/fwlink/events.asp) says a process was started and completed successfully, and then 6009 means system shutdown occurred, and 6005 means the shutdown was wrote to the log file.

It sounds like Windows is shutting the computer down for some reason when a certain part of the registry is scanned.  That should not happen.  Maybe it is due to a corrupt registry hive.  I don't know.