EDIT: I ran WCG several years ago so I added WCG as my first project to GRC with previously used user/pwd. Suddenly WCG did miss the part where pwd should contain more than few a-z an 0-9 and denied every attempt to change pwd to anything reasonable (like to quite simple crossroad of machine/human readable "1Gvo-5
I've had similar issues when cascading computers to other family members and/or trying to replace BOINC acounts on a machine. BOINC removal or change seems to leave a lot of residue.
I haven't done it for a while, but my memory says that the "BOINC Cleaner tool" here fixed my various problems with residue:
http://boinc.berkeley.edu/dev/forum_thread.php?id=4594Do your own research before using it though, in case my memory is incorrect.
WCG (great project) doesn't always play nice with the rest of BOINC or BAM, imho.