Windows 7 Windows 7 domain logon

Here's a strange problem.

I have an active directory domain controller running Windows Server 2003 at home. I am dual booting Windows XP and Windows 7 on my desktop PC.

I joined Windows 7 to the domain without problems, but when I log off and try to log back on to the domain using my username and password, I get a 'username or password incorrect' error.

If I type my domain credentials as:

[email protected]

I can log on to the domain. Then I log off and the same error appears. So, I use the following logon:

home\username

and can log on to the domain again. Then I log off and the same error appears. I use this:

[email protected]

and log on to the domain again. I can never log on to the domain the same way twice.

I have no problems logging on as the domain administrator and have no problems logging on to the domain using Windows XP.

Strange.

Any suggestions would be appreciated.