I deleted the SAM file - I ended up getting an error message stating that the file was corrupt or missing and I needed to reboot in safe mode. When I rebooted in safe mode I got the same error message and the computer automatically rebooted. I let it reboot several times with no luck. I finally decided to do a reinstall. I tried to do a repair install but that same error message kept popping up. I ended up installing "over the top", keeping the partitions and file system the same. That worked fine, with the exception of having to reinstall my MS Office.