How many gigabits are in a movie?

It depends on the quality or format that the movie is in...Movies come in .avi - divx - bluray - dvd5 - dvd9 - Highdefinition - others also.

The size is determined by those qualifications.

Lets just suppose that those 7 movies you refer to are DVD5 (standard vob-bak-ifo format) Then the size of those 7 movies (in Gigabytes) would be about 30 to 35 Gigs.