Troubleshooting services

We had an issue a few weeks ago with a particular service, which failed to start for an unknown reason. Checked the event viewer and the service dependencies, but these wouldn't give a clue towards what was causing the problem. Checked the internet for clues, but could not find a satisfying answer. Decided to download filemon from Sysinternals to see if this could give me a clue towards solving this issue. Installed and fired up Filemon, and tried to start the service. In filemon i could see which files where requested by the service, and discovered that it was missing a dll. Copied the dll from a working server, and reregistered it using regsvr32. After the dll was reregistered, the service was able to start.