There are articles about how to lock down Windows by doing that. It's a severe lockdown and is quite good.

-> If you want to recover the files that's easy. I can't guess which method you will use so I'll share the two I use the most.

1. Ubuntu LiveCD boot. More at http://www.howtogeek.com/howto/windows-vista/use-ubuntu-live-cd-to-backup-files-from-your-dead-windows-computer/

No install, just boot and get the files out.

2. Put the drive into some USB case and get at the files on a working machine.

-> In parting the moderators have always noted to have 2 admin capable accounts. Now you know why.
Bob