iMac wont boot

[WeeZer51402]

Hey every one as i posted in a previous post asking for help about using OF to boot (figured it out) my iMac just wont boot, i can turn it on it sounds like its thinking, the screen stays black and then it winds down, the only way it will boot is if i hold down the programers button on the side of the machine and either type in mac-boot or specifiy a device. the problem is i cant even reset pram(it wont let me use key strokes)

 

[Finch]

I had almost the exact issue not to long ago, just started I have idea why either? if you can get the machine booted via "mac-boot" I would suggest backing up and doing I re-install.