workstation service missing

hello,

I have a windows xp pro box (sp1a) that is missing the workstation service.
It doesn't show up at all in the services list in the control panel and I am
unable to start it by typing net start workstation. I get the error message
that the service name is invalid. Not even sure when this started happening
so can't explain what may have caused it. Is there a way to recreate the
workstation service? I have reinstalled the service pack but no luck with
it recreating the workstation service.

Any assistance with this would be greatly appreciated.

Thanks,

Joe