In Home the Built-in Administrator account should only be accessible and visible in Safe Mode.
Try booting into Safe Mode by repeatedly tapping the
F8 key after your BIOS POST but before Windows starts.
See if you do not then see a third (or Built-in) Administrator account. If so this account should be uncorrupted.
If this is the case you can try accessing all files via:
http://support.microsoft.com/?kbid=308421
You can also try creating new accounts and transferring data via:
http://support.microsoft.com/default...b;en-us;811151