Try the softwares at this link:-
http://www.soft32.com/related_downlo...D_TO_MPEG.html
All softwares given in above link are sharewares.
1ClickDVDRipper is given in some Digit CD.
Visit this site,as this has more converters:-
http://www.handyarchive.com/free/vob-to-mpeg-converter/