Tunebite works, but as i remember, this software decrease video quality. Because tunebite is based on screen capture technology.
I use to use fairuse4wm and it never fails. But it was years ago when i last time used this software. Last time....if i remember correctly, i converted one video for a guy, who is also member here (HQ approved....i believe). Joan Wise video. In april 2009. He gave me his username and pass....i downloaded video together with the licence, converted video to lifetime no-drm version and sended video to him.
I still remember....fairuse4wm keeps original video quality, converting takes only few seconds, but also you have to have blackbox-keys.txt file.... in the same folder as fairuse4wm software.
And then you have to change default wm-player settings. But i forgot how. Searched tutorials whole afternoon, but didn't found them.
Just use google.