Music, Video and Ps3 Question

Ok well i plugged in my usb device into my ps3 with my music in it, all are mp3s. But it says 'no tracks detected' or something. How do i get past that?

Second, how do I play my ps3 music in the background like on the 360, like even in games? Is it possible?

Thirdly same thing happened with the video on the usb, what do i do to make it detect it and how do i copy the video and music onto the hard dive?

ok. well when you see you usb device under the 'music' column, press the triangle button and press 'display all'. You should see your MP3's then.  The PS3 does not yet have the ability to play your own music whilst playing a game, unlike xbox. Hopefully system updates will fix this. Also try the 'display all' thing for your videos too. Once you see your videos/music on your usb device, press trianle on them and then 'copy' to put them on your hard drive:)