My Windows Vista x64 machine (not joined to any domain) has intermittent problems switching users. Sometimes, for no apparent reason, it decide that the "Switch User" option off of the Start menu or Ctrl-Alt-Del does absolutely nothing. Logging off still works, however, after I log off:
- The mouse cursor is invisible on the logon screen. The mouse is still active, because buttons on the logon screen will light up if I move my mouse around enough.
- There's an "Other Credentials" button below the password prompt that isn't there when everything's working properly.
- If I type my password and press Enter, I get the following error: "A device attached to the system is not functioning."
- Trying to restart the computer (using the "Power" button at the lower right corner of the logon screen) does absolutely nothing.
- Trying to shut down the computer (using that same button) instead puts the computer into sleep or hibernate mode. When I turn it back on, it's still having problems.
So far, the only solution I've found is to hold the power button for 5 seconds to force the computer off.