You could always just uninstall as administrator, login as your service account and reinstall that way. Its the cleaner, less band-aid approach to the situation. Database would remain intact and you would only have to add the users back (which you can simply export those and import them back, losing no info). I would say that, with the reboots, it would be perhaps a 30 minute process (depending on your hardware since the reboots would be the longest part if you have a RAID controller and whatnot).
In the beginning the Universe was created. This has made a lot of people very angry and is widely regarded as a bad move.