Originally Posted by JD Gumby
Hook your Arc up to your computer. If it doesn't open automatically (usually won't), go to Start -> Computer -> Portable Devices -> Arc -> Internal Storage and then to a directory of your choice (I suggest "Movies", in this case, to make it easier to find). Then just drag and drop the file you want from your computer, confirming that you want to copy since Windows will most likely complain that the Arc can't play it (Windows doesn't know what it's talking about :P).
Then it's just a matter of opening the file by going there in a file manager (ES File Explorer's a good one) or, with movies, you can just open up the Gallery and it should be right there if you had placed the movie in the Movies directory.
Does it take a long time to load, it says the movie is loading but its been like 10 minutes now