Spent several hours trying to figure out why my niece's computer was rejecting all login passwords. It's a new, well 6wks old HP Slimline machine sporting Vista.
What was crazy was that F10 would not let me get into the bios screen F8 often didn't get me to the safe mode choice screen, and when it did, the system never actually booted into safe mode.
Finally used
this to clear all passwords. After that logins worked. Used the control panel to reestablish passwords, logged out/in switched users. It all worked. Rebooted the system, Baloowie. All passwords rejected again. Once more around the mulberry bush we go.
During this session, while trying to type a path I finally notice, I can't type "/". Only "?'s" show up. WFT??
Opening notepad and trying various keys, every thing typed seems shifted. Using shift or caps lock seems to cause changes, but it's inconsistent.
Go find another keyboard and swap it out and everything is fine.
Blinking Keyboard!!! Who would suspect that a brand new kbd would fail in such a flaky way.