Can I convert just VOB files with DVD Ripper Professional ?
It depends. If you just have VOB files without any corresponding IFO files, then you cannot use DVD Ripper Pro to convert these file. You would need to use Video Converter Professional. If you have IFO files, then ensure all your IFO, BUP and VOB files are in a folder called VIDEO_TS and open that folder using Open DVD on Hard Drive function.