I was fixing a friend's uncle's computer running Vista Home a few weeks ago, and he had an error message regarding an unauthorized change to Windows. It would boot into a limited functionality mode that essentially just gave him access to the MS Genuine Advantage page via an IE window, but no start menu, documents, etc. I ended up doing a system restore and all was well for a few days.
He contacted me again a few days later saying on system start, it was prompting him for password to authorize something (he couldn't remember what) so he clicked cancel. After that, it was back to limited functionality mode. Since system restore seems to have been a temporary fix, I ran sfc/scannow, and it says it found some corrupt Windows files but was unable to repair them. It saved a log file which I can post upon request if anybody would be willing to look at it, or I can look at it myself if anybody can tell me what I'm looking for . Another forum had recommended using the find function to search for "Cannot Repair" in the log, but there were no hits on that particular term.
The odd thing is, on restart after running sfc/scannow, Vista was back to normal. I put the machine through 3 restarts, ran some programs, and everything seemed fine. I'm still not convinced I've addressed the root cause of the problem, though. Any input would be appreciated, but please understand I don't have easy access to the machine since it is not mine, so it may take me a day or two to run additional tests or go rooting around in his registry if you need to see anything besides the SFC log.
Edited by Molotov256, 26 April 2011 - 07:02 PM.