Affiliate Marketing Secrets

i have various DVD’s in IFO, BUP, and VOB file format. think of a film and the film is made up of these formats. now i want to convert the film from these formats into 1 AVI file how do i do that? the software you tell me about has to be totally free to use, no trial versions or me have to buy some expensive piece of software … im broke.
the reason i need this information is once i can convert the files (without losing sound or picture quality) i can then sell copies of the DVD’s (there in the health and fitness niche).
all help will be most appreciated