changing admin passwd

There is something seems strange to me that when i change the administrator password of the machine, sql server is not starting due to the problems of network.Anf forcing me to use the password that i give at the setup of win2000.Why does it occur and what do I have to do?By going to Control Pannel--->Adminsitrative Tool-->Services-->MSSQL SERVER..Double click on that and enter the new password.It should work then.