I don't recommend modifying a service's LoadOrderGroup, but it can be done with
sc.exe from the command line.
C:\>sc config /?
Modifies a service entry in the registry and Service Database.
sc <server> config [service name] <option1> <option2>...
NOTE: The option name includes the equal sign.
A space is required between the equal sign and the value.
depend= <Dependencies(separated by / (forward slash))>
DisplayName= <display name>
The part you're interested in is
group= <loadordergroup>. This says that the list of valid LoadOrderGroups is in a value named
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control, but I found in Windows 7 that there is no such value. There is a key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ServiceGroupOrder with a value
List. The data for
List is obviously a list of the groups, in the order that the groups get loaded.
Once again, I wouldn't touch any of these configuration settings unless you're certain you know what you're doing. I have no idea what problems you might cause.
Also, be advised that
sc.exe is extremely picky about syntax.
sc config messenger DisplayName= Messenger works.
sc config messenger DisplayName=Messenger will not work.
sc config messenger DisplayName = Messenger will not work.