jioning a network

i recently took a computer off the network and change it from a domain to a work group know i need to rejoin the network here’s the problem i can map the drives that it had but when i try to join the domain it tells me that ( the cerdentials that i supply conflict with an existing set of credentials) i have went to the W2K domain controler and reset the the computers acount I tried to delete the computer and rejoining the domain same error message