I won't write the walkthough here (it's on the internet) but I've never been locked out.
Besides you should have a spare admin account. Your story is one of the many reasons why we keep a spare.
My Vista Home Premium machine normally asks for my password when awakening upon sleep mode. A couple weeks ago, it stopped asking for the password when awakening. Then a couple days ago, it started asking for the password again upon awakening. I put in the password but it strangely didn't work, even though I didn't change the password. I could still get on the guest account.
Then a couple days later the password starting working again. Then a couple days after that it's back to not asking for my password when waking up from sleep mode.
Any ideas as to why this occurred? I want to do what I can to prevent myself from getting locked out of my account again.