I hope I'm posting this in a right place.
I have problems with my laptop, Win 8.1... I bought it a few months ago, so it's new, and suddenly (few days ago) sound stopped working.
I did make some changes right before that (cleaning with Advanced System Care).. and problem started when I restarted it... I get the error in Windows Media Player "WMP encountered a problem while playing the file.", and while trying to test any sounds: "Failed to play test tone", but it seems that everything is OK. I can't find any hardware/driver problems..
I use Advanced Sys Care from the beginning, and it never caused any problems, so I'm not sure if he is the guilty one
I tried roll-back option in Adv.Sys Care, and Windows' restore point... It didn't work..
I also tried everything from reseting sound settings, reseting audio services, uninstalling everything that has something with the audio from device manager, reinstalling and also updating all drivers... Even though the COM+ Unmarshalers registry is there, I tried using Windows Repair (all in one) as I found some suggestions on google.. (Unmarshalers exists, but every registry inside is empty.. So there are a lot of subfolders in it, each with one registry with "(default)" name and under data it says "value not set".. I'm not sure if that is the problem..)
I don't know what else to try..
Sorry for my bad English and long post, I hope I explained it clearly enough..