"Other User" phantom account

Hopefully, someone can help me resolve this issue. I'm not sure what I did, but when I reach the Windows logon screen, I'm offered two choices: my account and "Other User". In the past, there was only one choice: my account. I tried to logon under "Other User", but I don't have the password for this account, since I didn't create it purposefully. It just appeared one day. The "Other User" account doesn't show up in Control Panel > User Accounts.

I'm wondering if anyone know how I can disable this account.

Thanks for your help!

Wondering if you ever got this issue resolved? I seem to have run across a simliar issue. After Vista boots, it trys to log me into a phantom account. I had deleted the account but the login still exists and it doesn't show up in the User Accounts. Although I enter the correct password, it comes back to the login. I can change users and log in, but I'm not sure how to delete the other, non-existent login.

Thanks.