OSX installation fails (reboot before any screen comes up)
After starting upgrade from 10.6 to 10.8 the system don't started. I tried to reinstall 10.6 from DVD and USB stick, but before the initial setup screen come up the system restart. the same happens with 10.8.
There is also no possibility to use the recovery disk Assistant, the system restarts before I see any screen.
If I use a Windows7 DVD I can install it without any problem. Does anybody have a hint for me what I can try to get my OSX back?
As soon as you hear the chime press and hold down the COMMAND- R keys until the menu screen appears. Alternatively, after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD
You might try holding down N for a network boot, (you'll have to have a computer running the install disk on a shared optical drive.)
First you must erase and reformat the HD you can't install an OS on a corrupted HD.
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Do you have a second Mac? If you do you could try connecting the MBA in target disk mode (hold the T key when it boots) to the other Mac using ThunderBolt. That way you can access the drive without accessing the boot sectors so you can rebuild things.
You may need to update your EFI firmware (Apple TN on EFI update 2.2)
Otherwise you may need to pull the drive out and mount it to the other Mac via an external HD case to access it (if your MBA doesn't have TBolt).