Welcome to the forums.
You will have to have a dvd drive connected to your laptop in order to work with dvd movies.
Getting the movie onto the hard drive requires a decryption/ripping program. The type of protection on the movie varies, some are harder to get rid of than others. You should get DVDFab for this decryption. There is a free section of DVDFab, called DVDFab HD Decrypter, and it will continue to decrypt and rip the movie for you even after the trial for the main part of DVDFab expires. Found here: http://www.dvdfab.com/free.htm
Once you have the dvd on the hard drive, you can take a section from it using DVDShrink in ReAuthor mode using the Start/End Frame tool. Just click on DVDShrink in the previous line to go to the download here at cdfreaks. You should read some guides for using Shrink either here in our Movie Copy Software forum, or at www.mrbass.org or www.dvdshrink.info
ISO file....think of it as a snapshot of the entire disk: In addition to data of the files it also contains all the file system metadata, including boot code, structures, and attributes. Taken from Wikipedia