ok so i have a portable 40 gig hard drive. and when i connect it to my 360 it registers and it works fine. but if i put any of my movies on it the 360 doesnt read them. nothing pops up. if i put a picture on the hd, i can see it on my 360. but if i put any of my movies on it. the 360 doesnt "see" any of them. is it some kind of formatting problem? i know computer basics, but im no it genius. i really wanna watch my movie files on my 360 please help!