iPhone won't turn on -- black screen, not recognized in iTunes, etc

[itskerem]

Hey guys,

I know this is a little off-topic, but this forum has been super-helpful to me before, and I'm not finding answers anywhere, so I'm going to give it a shot.

My battery was low last night, but not dead yet, so I started charging my iPhone on my laptop. After a while, my iPhone just turned off -- totally black screen, unrecognized by the laptop & iTunes, doesn't respond to anything. This seemed to happen out of nowhere.

My top button only works sporadically, so I've tried resetting & whatnot, but I have no way of knowing if that's really working.

I've searched everywhere, but most of the troubleshooting advice I've seen assumes that the phone is visible in iTunes.

Help is much appreciated, thank you.

iphone 3g 8gb
firmware 3.1.3
jailbroken with redsn0w 0.9.4
baseband 06.15.00
bootloader 6.4

update: Tried restarting computer with iPhone plugged in. Didn't work.

[itskerem]

anybody!?