Password

I have a dual boot with XP pro and XP Home. I installed Vista Premium on the
XP Home hard drive. Everything works well except that now when I try to boot
to XP Pro, it will not let me logon. I have the username filled in(Mike) and
password blank. I have always been able to click enter and it loads up.
Now I get this error:
The local policy of this system does not allow you to logon interactively.
If I put anything in the password area, I get this error:
The system could not log you on. Make sure your user name and domain are
correct, then type your password again. Letters in passwords must be typed
using the correct case.
Any help?
Thanks for your time, Mike