we have an x64 sql server on windows 2003. it also has a 32-bit install / named instance (so we can get our 32-bit linked servers to work). the instructions above worked for the x64 instance, but not for the 32-bit named instance. when hitting apply, an error dialog appears. my workaround was to change it manually using services.msc. the new account was already a sysadmin, so everything seems to be working fine.