"No Mapping between account names and security IDs..."

Hi All: I had a standalone 2003 server sp2 in a domain running IIS/SQL2005, and I decided to promote it to a DC without doing too much research. After promotion/reboot, SQL did not start and I saw pretty quickly that it had been running under a local account that no longer existed.

I created a domain user to assign to SQL, opened SCM and tried to change the log on, but when I click "apply" I receive a popup with

"WMI Provider Error"

"No mappeing between account names and security IDs was done. [0x80070534]."

I've been googling around but haven't figured out what to do to fix this?

.