"Windows Service Pack Installer update service"

I see this entry in my system services list, listed for automatic startup, but not running. From the (very) limited information I could gather on it, it says it's a run-once service that makes some necessary modifications after installing SP3 for XP. I'm guessing it never fired because I have it's dependency "Security Accounts Manager" disabled.

So my questions:

Being run-once, will it then vanish from my system service & startup lists afterwards? If not, what should I set it at (manual, disabled)? Does it need to stay running?

What exactly does it do? SP3 seems to be working fine regardless. Is there something I've been missing all this time?

There is very little information on this service as it's a new one. It can't be found on any of the lists (i.e. eldergeek/viper) that you can find all over the net. I figured some members here could give me some information.

Thanks in advance

 

http://lyle.smu.edu/~kaytaz/xpservices.html

I know it's old topic, but just in case someone comes here looking for the answer

 

Look at Event Logs for any errors or warnings on this service failed to start. If it failed to start because of dependency, I would start Security Accounts Manager (dependency, set it to automatic) and reboot. If Windows Service Pack Installer Service is indeed a run-once type of service, then I guess it will not go away until it's started and finished with it's job. When all is finished you can set dependency back on disabled.
Just a suggestion.

I didn't do my homework so I cannot answer what exactly this service does, but I can give a comparison. NET Framework has a service that needs to run after the installation and reboot in order to recomplie it's Base Class Libraries. Once it's done it will go away. So what I'm saying is that these kinds of services (run-once) were used by Microsoft before.