Resetting Macbook Air failed - now nothing works

Hi

I've tried resetting my Macbook Air, but now nothing works.

I started the macbook using command + r - then went into disk utility to make a clean install.

Next I tried using the reinstall OS X option, but it fails with "currently not available" error.

Then I tried internet restore by holding down option + command + r - this went all the way through the progress bar, but then just showed a grey screen with a stop sign on it.

Since the macbook was origianlly installed with Mavericks I cannot use the shirt + option + command + r

I the tried creating a bootable usb drive using a Mac Mini I have. Using the application "Create install disk", but my Macbook won't recognize the usb as a start disk, so don't know how to start the installation from there?

I also tried to reset NVRAM, but I do not get the behaviour described (second startup sound) so don't think it works.

I can run the command + r and get to these tools, can I from here using the Terminal or something trigger the installation from my usb?

Hope some can help med - already thrown many hours at this problem :-(