[WIN7] Login Won't Accept Password

Having an odd issue here.... We have two administrator accounts setup on the computer. One is the end user, the other is "Admin". The "Admin" account refuses to accept the password. I can login as the end user, and since they have administrative rights, I can reset the password for "Admin". But even after doing that, Windows 7 still tells me the password for "Admin" is incorrect. Any ideas? Thanks.