For the DCOM errors, try following the instructions here:
Application Specific Permissions Settings Do Not Grant Local Launch ...
The components hive being corrupted then recovered is a problem, sfc and other tools will not function correctly if it is has inconsistencies - I won't be able to address this right now.
I would like to try and trace what exactly is occurring when the test tone fails to play.
Follow the instructions here:
How to Capture a Process Monitor Trace, start process monitor, attempt to play the test tone, then stop collecting data (CTRL+E) immediately after you receive the error.
Save and zip up the pml file then upload it with your next reply - I'll see what I can find.