First of all you dont have a 4gb because they dont exist. As for videos/movies you have to downlaod the AMV Conversion software from the downloads section here on this site to convert your movie or videos into the AMV Format so your player can play them. Click this link
http://www.mympxplayer.org/viewtopic.php?t=32 to learn how to do that after you download the software. And to put music onto your player you simply click on MYCOMPUTER and then double click on the drive that shows up as your player which mine is F
rive yours may be different and then drag and drop your music files into it. Good luck!.