Keypad unresponsive

I just got a M6 2GB recently, so it already came with the newest firmware. The player was on, I was listening to a song, and I was trying to adjust the volume. The keypad suddenly became unresponsive: I couldn't pause the current track, I couldn't return to the menu...etc.

Right now, the player is still on, playing the current album, but the screen is black and nothing I press is working. I've tried holding various buttons down (the "enter" key is the middle between the fastforward and rewind, right?). I imagine it will shut itself down when the album finishes playing, but in the meantime (and even when it does shut down), I have no idea what to do. TT___TT

The player has now stopped (guess the album ran out of songs). I've connected it via USB, and there is no response at all from the player (the screen doesn't light up and my computer isn't registering an external unit).

Help please?

turn it on b4 u plug it to ure PC