If you don't mind recoding the video and/or audio, I would recommend using staxrip. You can add or transcode two audio streams, but if you are wanting to add subtitle/subpicture streams, I really haven't figured out a way to do it yet unless you encode the video with staxrip and mux the 264 file into MKV with the audio and sub streams using mkvmerge. As ps355528 said, you *should* be able to mux it with mkvtoolnix, but if the video is corrupted or something you may need to recode it. If you can extract the video and audio streams, you should be able to mux it using the gui version of toolnix. Or, like I said, you can recode the entire thing with staxrip and that should work although it will take longer. If you're still having problems, let me know more specifically what they are, and I'll see what I can do to help.
Originally posted by ps355528: just rename it.. ogm is a valid format to put inside a mkvwrapper
Seriously?... lol
You can at least suggest googling "ogm to mkv"
There are many free programs that can convert ogm to mkv, or demux ogm, and then remux to mkv. Like OGMTools, and MKVtoolnix. And several GUI front-ends for those, as well.