Windows Installer

Windows installer service is corrupted somehow. i can not start office applications or any other aplication. Also i cant start any installation setup file. I have downloaded the Installer from Microsoft site. but i cant install it because the service already exist. When opening the services under Administrative Options, i couldnt find an oaction for deleting an existing service. ( there is only Start, Stop, Restart , rename and Pause)

So any body knows how to delete a service in 2000 Profissional ??? I am administrator on the machine by the way.
Shall i edit the registry to delete the server .. if yes then how ?

your help is very much appreciated