I used the following command:

launchctl unload -w /System/Library/LaunchAgents/com.apple.notificationcenterui.plist

in an attempt to disable notification center. I'm not sure that I got all of the commands right and appear to have corrupted the account that I executed it from - I get a grey screen when I try to login on that account. Fortunately I have another account on the machine with admin privileges so I can still use the machine. I would however like to restore the account to a working condition preferably without having to resort to a complete system restore from my time machine backup.

Is there a way of diagnosing the current status of this launchagent and returning it to its original state?