firstly, wat is a MDF file? i've downloaded a movie in this format. i've asked one of my friends, he said i can open it with daemon tools or alcohol but they didnt work and i thought i could unzip it with winzip but it didnt work either. please help.

Alcohol can open MDF file~
but MDF and MDS are in pairs, you need both of them to open the file
there should be a mdf and a mds file in the same name, mdf is the main body with large size, and the mds is usually very small...