MacMini not booting - grey screen

[minimac2]

Hi. I have a problem with my macmini (2012, maverick, bootcamp -win8). I cannot boot any more. I hear just the chimes sound and get only a grey screen. I tried resetting pram but i couldn'd. Nothing happens, when i press "alt-win-p-r". I also tried all keyboard-combinations (SHIFT,ALT-R etc..) on a apple usb keyboard. No luck with this too. I just see a grey screen. I did everything what apple is suggesting: http://support.apple.com/kb/HT1379?viewlocale=de_DE. No Luck too.

The last thing i did was on Maverick "Preferences => Boot from bootcamp".

I readed in many forums, that the first chimes-sound means, that all hardware is OK? Is this right?

What can i do now? It is not possible to reinstall, because i get just a grey screen.

Does somebody has this problem too?

 

[blanka]

Can you boot into Target-disk mode (hold T during boot)?

 

[niteflyr]

Some info:


http://support.apple.com/kb/PH14062

To re-install, Command+R boot to recovery.

 

[minimac2]

The Shortcut "T" is not working too. It seems that no shortcut works at startup. I tried it with a cherry usb keyboard and with the original mac usb keyboard.

Does the chimes-sound not mean, that hardware is OK? And how can i reinstall macos, when no shortcut at booting is working?

PS: Neither the indicator light on the keyboard nor the mouse is lighting. I connected my usb-stick. The indicator-light is here working!

 

[Fishrrman]

Try this:

Power all the way down, completely off.

Wait 30 seconds.

Press the power-on button.

Hold down the option key (no other keys) and KEEP HOLDING IT DOWN.

After several seconds, what do you see?