Shared folders require password

We were using W98 in a peer to peer network w/o any problems. Upgraded one of the computers to W2k Pro, now attempting to access one of the shared folders or the shared printer on the upgraded computer, opens a dialog nox requesting a password. We did not have any password before, a blank will not work, no pw is required to boot the W2k computer. Please let me know how to solve it. Tahnks