while playing your dvd, open audio audio and open a new wave form, set at 44100,stereo, 16bit.
now click on options at the top and click mouse on windows recording mixer, voluome box opens (make sure stereo mixer is showing and place a tick init and set volume half way. now just play the dvd and when the track or song comes on click the record button on audio audition . and when the song is finished click stop and save the file as a wave format or mp3 etc ..
cheers and beers