My 17" 1229, had the same thing; I opened it up from sleep and black screen. I could shut it down by pressing power once then the enter key. External digital monitor out of the DVI port didn't work either. I did the remove battery Op&Cmd + p&r reboot; without luck too. Called Apple, they sent me a box to put it in and I had it back in a few days fixed with a new logic board; FREE as in No Charge for anything. (2yrs old; no Apple Care plan) It was the chipset on the Nvida graphics card; which was recalled.
Answer to: Black Screen - PRAM - No current