Set default action for CD/DVD/BD/Etc

Actually there is another way that could be checked and sometime more appropriate:

I noticed that the default (bold text) action changed, when I went to Computer/Manage/Disk Management and I changed the drive letter of the media in question, to another unused letter and the default action changed back to the standard one 'Open'.
So there is another key that can be used to reset the default action of Drives/Removable Media/Mount Points and it is:
HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\X

Where X is the drive letter where you want the default action to change.

Ulterior sources
https://superuser.com/questions/3357...ia-be-disabled

THANK YOU for this post...I was going out of my mind because my computer wouldn't play DVDs - modifying AUTOPLAY etc did nothing! I managed to sort out my DVD problems AND I found the key req'd to change your default player for CDs - it is at HKCR\AudioCD.

To change the default player for CDs it's just like with DVDs

For CDs - i found the key at:
HKCR\AudioCD

Hope this helps!
The rest of the instructions are the same...as with HKCR\DVD, you need to simply change the value in
HKCR\AudioCD\shell\play\command

You should have one STRING value (default value) in that key; value data should be
"%ProgramFiles%\Windows Media Player\wmplayer.exe" /prefetch:3 /device:AudioCD "%L"

Change this to "<path to your desired default program>" /prefetch:3 /device:AudioCD "%L"

(for DVDs, the key is at HKCR\DVD\shell\play\command -->there is one STRING value (default value) in that key which contains your default player : "%ProgramFiles%\Windows Media Player\wmplayer.exe" /prefetch:4 /device:DVD "%L" -->you can modify the default player by changing the value as follows "path to your desired default player" /prefetch:4 /device:DVD "%L")

Hope this helps!
-str8arrow