SQL Server 2000 SP5a on Windows 2000 SP4

Friday morning we discovered that we no longer have sysadmin
privileges. We were able to query the syslogins table. In the output
we can clearly see that our accounts do have the sysadmin privileges,
since there is a 1 in that column. But yet we do not have sysadmin
privs!?!?!?!??!?!? Puzzling.

We are not able to get into the SA account, since no one knows the
password. But we are in BUILTIN/Administrators, and we have many SQL
Server authenticated accounts with sysadmin privs. But yet none of
them seem to have the privilege.

Saturday I was able to restart the instance (actually, several times
now), but that does not seem to resolve the problem. I have also
rebooted the server, which does not solve the problem.

The next option would be to restore Master from a few days ago, but
since I have no privileges I cant even do that!!!

Help? Ideas?