While installing a webpart for Sharepoint today I had the installer routine advise that the timer service was not started. Which the services list told me was incorrect.
After a bit of messing around the solution was to use the Run as Administrator option for the installer.
But, the program list did not offer the right-click option, so I used a command prompt with Run as Administrator and ran the installer from the prompt.
The reference that helped was at codeplex.