Put this into a .reg file and run:
Code:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.ogm]
"PerceivedType"="video"
"Content Type"="video/x-ogm"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Extensions\.ogm]
"Runtime"=dword:00000007
"Permissions"=dword:0000000f
"UserApprovedOwning"="yes"
[HKEY_CLASSES_ROOT\.mkv]
"PerceivedType"="video"
"Content Type"="video/x-matroska"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Extensions\.mkv]
"Runtime"=dword:00000007
"Permissions"=dword:0000000f
"UserApprovedOwning"="yes"
This will *only* work if you can already play the content in WMP (ie. have the codec installed already )