SQL Authentication error on password change

I have instaled SQL Server2000 in Administrator user login.My OS is Windows Adavance Server2000. It works Fine. If i change my Administrator Password and Login with the new Password then Sql Server dosn't Run.It says Authentication error if i try to run from service.
I belive DBA's in this forum can help me out.

you have to change the password in the MSSQlserver and SQlServerAgent service account as well and restart the service.

Thanks MAK!!!!