Help No screen

i have a 512mb mp3 cube made by select and when i first got it a screen appeared when i connected it via usb but it the screen wouldnt come up when i took it out of the usb so i installed a firmware and now the whole thing doesnt work and the screen wont come on and when i connect it to the computer it picks it up as a removable disk for about 5 seconds then it stops picking the mp3 player up, i have formated it but how do i get his working again please some help!