Uninstalling the service pack is not going to help as it now means your system is unsafe as it is now unsupported by Microsoft for security updates. Support for Vista SP1 and under ended July 12 this year. I would strongly advise you to reinstall SP2 and update as there have been dozens of updates since then. A few reboots and updates later you may find things start to work as they should,
All this sounds like to me is that a few drivers need to be updated.
Microphone : check for soundcard updates
Media Player Classic is not supported in Vista anyway as far as I know, or at least the original version isn't. Check versions.
DVD drive firmware probably needs updating.
Also check your Windows Update for any updates that you may have hidden.