ok, i've done my own test.
if you have latest patch 4223, you'll notice files have play with powerdvd. there are too many to handle through regedit, but a quick fix is to install the beta uninstaller provided by michael in the 1st beta update. then remove it. this will take care of file associations. in terms of disc types,
hkey_classes_root\___\shell\PlayWithPowerDVD14.0
dvd
bluray
audiocd
endvd
mixed
musicfiles
pic
svcd
vcd
videofiles
you need to delete the folder playwith....
consider this a beta context menu fix. i have done test but aren't absolutly sure until i have more time.