This is for anyone running Sharepoint on Microsoft Windows Server with MS-SQL and you are getting an error along the lines of SQLAgent is not allowed to run
All you have to do is make a small registry change. Navigate to:
HKEY_LOCAL_MACHINE/ SOFTWARE/ MICROSOFT/ MICROSOFT SQL SERVER/ SHAREPOINT/ SQLSERVERAGENT
Look for the key GUID and delete it.
the SQLAgent service should now start up without problems.
I had a heck of a time figuring out this problem but after some searching this seemed to do the trick.