macbook air usb boot

Installing only Windows on a Mac computer can be problematical. You will have difficulties with drivers. You are better off installing a minimal OS X installation, then installing Windows using the Boot Camp Assistant:  https://support.apple.com/en-ca/HT201468

You can make the Windows partition into a large partition, just leaving 10 Gigs or so for the Mac partition.

That also leaves you with a bootable Mac partition to reinstall Windows from if you Windows installation dies.

See also:  http://www.apple.com/ca/support/bootcamp/

Hello strung

my problem is that booting from USB is not possible - neither OSx from a USB DVD Drive.

Do you have another Mac available, so that you can connect the two and use Target Disk Mode?

If so, please let us know the models of both Macs and what OS are on them.

If you have a wifi connection, you can use command option r to restore the original OS from Apple's servers over the internet.

Model of the Mac would be helpful.
Why is the hard drive blank? Has the MBA been dropped or liquid spilled?
Does the MBAir chime and screen appears with ?mark folder
Does the MBA with CMD+OPT+P+R keys down chime more than once, until keys released?
"T" key down at startup, does a large icon appear? Target Disk Mode explanation here
http://www.theinstructional.com/guides/high-speed-data-transfers-between-macs-with-thunderbolt
OPTION key down at startup, does a boot manager screen appear?

Following an iFixit guide and temporarily removing the SSD may change it's behavior (unlikely)

Bootable USB with OSX on it should be partitioned GUID and formatted HFS+ (Journaled)
OPTION key at startup should show the OSX USB drive as an option.

Thunderbolt port is on MacBook Air (Mid 2011 and later)
http://everymac.com  gives the specs on all Mac Models
The A1234 number on the bottom of the case is the case model not the mac model.


Startup Keys Listed
https://support.apple.com/en-us/HT201255

CMD+OPT+P+R is the answer.