My guess is that somehow, those services got deleted or something. My only assumed resolution would be to "Repair" Windows. To do this, you would pop the install disk in, boot into it, and, when it asks you if you want to Install Windows, or "Repair" it with the Recovery Console, press your enter key to "Install Windows". Once it is looking at your Hard Drives, it will detect a "Previous" version (i.e. the one you already have installed but are having troubles with) and you will press the "R" key to "Repair" it or w/e. Basically it will just recopy the files that it finds are missing.
Hope that helps

(because I can't think of anything else that I would do)