Don't recall how it happened, but my boys' PC only has one account active, and it is a guest account. Several related points:
- When the UAC prompt pops up, it asks for an admin password, but gives no place to enter one.
- I cannot run anything as an admin because of no ability to enter a password.
- I used the install disk to open a command prompt on the repair screen and entered "net user administrator /active:yes". When I rebooted, I saw two accounts: my boys' account and one labeled "Other User" that required entry of a user name and a password.
- I cannot get my PC to boot to safe mode. F8 doesn't do the trick and "msconfig" requires an admin password that I cannot enter.
- System restore only goes back a few days, and that's not far enough.
- My antivirus is up-to-date and says my PC is clean.
At this point, I'm about to wipe and reinstall the entire OS unless someone has a better solution.