I have built a virtual machine (Window XP). I have no trouble logging
in using my domain account for the first few days. Now I could not
login, with the error message: "Windows cannot connect to the domain,
either because the domain controller is down or unavailable or because
your computer account cannot be found etc".  If I type in a wrong
password, I got "The system could log you on. Make sure your user name
and password is correct etc". This, to me, means that I am talking to
the domain controller and the controller is up and yet my account is
not accepted with the associated Virtual PC. If I login using a local
account. I can see my domain account as a member of the administrator
but it is all in numbers, like  S-1-5-21-21134...... If I remove this
account and add my account again, the computer accept and retrieve my
account info, but upon saving, my account is turned to a whole bunch
of number again and I don't think the machine is binded to the domain.

Any idea what happens?  Thanks.