Try this:
If you have Home, boot into Safe Mode (F8 after the post test and before
Windows starts. Once Windows starts loading, you've missed it and will have
to try again). At the menu, select Safe Mode and press enter. At Safe Mode
you'll have an option to log on as Administrator; type
administrator, leave the password blank and press enter.
Then, right click a blank space on the desktop, select properties, go to the
Screen Saver tab, remove the check next to "On Resume, display Welcome
Screen," click apply and ok.
It sounds as though the above is the issue and once that check is removed,
it should not lock you out again. I'm surprised it didn't give you an
option to enter your password and ID which is why I'm not completely certain
the above is the issue and as such fix the problem.
If it doesn't return to safe mode as above but accept the option to go to
System Restore when you get to Safe Mode and try using that to take your
system back to a time prior to when this began.
