I realised this when i was having issues with Firefox browser on my machine, i tried to uninstall it, however, when it came time for the UAC to pop up (which i have disabled) my machine hung up for a few seconds, then told me that windows explorer has stopped working and is now looking for a soloution, so i tried to change the UAC settings, and to actually change those settings, i must go through UAC to get to it...which also hung up. So i can't troubleshoot, can't uninstall programs, and i can't change UAC settings in control panel. I've taken out my AVG antivirus out of startup, done a chkdsk on my local hard drive, booted into safe mode and it gave me the same thing...Ive also done a clean boot and a system restore still with no luck. any answers would be dearly appreciated.