Is there a way to configure a Windows service process (e.g. squidNT, SQL Server, etc) to start automatically with low priority without manually changing process priority via Task Manager?
The Service Control Manager, which handles starting / stopping services, doesn't have any mechanism (in any version of Windows heretofore) to specify the priority on processes it starts.
Since you can modify the priority on an already-running process, your best bet might be to use a tool to do that.
I'm not aware of a Microsoft command-line tool to modify process priority, but the "PV" command-line too, available at http://www.teamcti.com/pview/prcview.htm has a function to set priority.
That would set "process-name.exe" to "Below Normal" priority.
If you can live with the process starting out at "Normal" priority until you get around to changing it, you could do so with a script running as a "Scheduled Task" to fire off every-so-often (in case the service gets bounced).
It's a quick and dirty hack, but I owe a lot of my fortune in life to quick and dirty hacks that get the job done!
The following might also work. Edit the ImagePath registry key, and use the start command from cmd.exe:
START ["title"] [/Dpath] [/I] [/MIN] [/MAX] [/SEPARATE | /SHARED] [/LOW | /NORMAL | /HIGH | /REALTIME | /ABOVENORMAL | /BELOWNORMAL] [/WAIT] [/B] [command/program] [parameters]