Help with Windows Network.

Have two windows networked computers, one running Windows200 proffessional and the other running Windows ME, the later cant look into shared files on Windows 2000 computer. However windows 2000 computer can access shared files on Windows ME computer. It keeps asking for password when trying to access from windows ME computer, but the passwords are not recognised.

What should I do so Windows ME can look into files on Windows 2000?

Thanks.