I am running vista and get the following error too, "the windows
installer service could not be accessed. this can occur if the windows
installer is not correctly installed. contact your support personnel for
assistance." when trying to install certain programs, but not all of
them. I have treid all the suggestions i could find on microsofts kb.
Along with, checking that the service is running and is set to manual
and is started, trying to install in safe mode, trying to do a clean
boot with needed services, and quite a few other things. if someone can
give me a solution to this problem i will love them forever.