Enter one of the forums where lovers of cinema, for example, the following - http://kino.10bb.ru/ Then find the theme on the movies. It can be common, and there may be several for different genres. Sign up for writing messages is definitely on most of these forums.
Next, write a message, which give the maximum information about the film - its genre, content, names of the main characters, any memorable small details, country and year of issue. It is possible that among the readers of this topic will be a person who remembers the name you are interested in and notify you.
Re-read the already existing topics search on the forums. It is possible that someone already asked the question about the name of the same movie and got the answer.
Search for the movie on specialized sites-directories. For example, you can help Russian-speaking resource "Kinopoisk" and the site with the most complete information about the various films - Internet Movie Database (IMDB). One of the sites, select "Advanced search". You will see a list of keywords which describe the content of the film.
Select one or more of them and click "Search". The system will give you a list of movie titles, and among them may be the one you need. But note that such list may come across descriptions of the films without the outline. In this case, you will be able to navigate on the posted stills from the movie, poster and cast list.
If the above search methods did not help you, ask a query through the search engine with the key words from the plot of the film.
After you specify the name of the movie, buy it in the store or search the Internet in the public domain. In particular, a large number of films placed on the lawful bases, can be found on the websites of Internet service providers.