Can only boot to Windows 7, no OS Back in late 2010, when I first got my MacBook Air, I followed the instructions at http://howto.cnet.com/8301-11310_39-20020513-285/install-win-7-on-macbook-air-from-a-usb-drive/ to install Windows 7 on the metal (not virtualized).

I've been thrilled with it until recently when battery life began to flag. I reinstalled Windows today expecting to lose some cruft I've inadvertently gathered over the years, and regain some performance/battery life. I'm now no longer able to boot into Mac OS X, and did not mean to lose that functionality.

I can't use any of the methods above, because I can't boot to the point that the chime sounds. All I can do is boot straight to Windows 7. The real issue right now is that I can't get on my network using either the built in WiFi adaptor, an external USB WiFi adaptor (Alfa), or using the Apple USB to Ethernet adaptor.

Any help? I'm at your mercy. The Apple store is a good trip away for me, but if nothing else works, I'll try having a restore done there from the network. But if they can't boot to right stage either, I'm afraid I'm hosed.
It sounds like the Windows reinstall overwrote your boot sector on your mass storage device.

I'd attempt to reinstall rEFIit, under Windows, and see if you can get the option to choose your boot partition on boot up again.  If that doesn't work, there's a new tool called 'rEFInd' that is actively being developed.  There's a good article here on using the tool with an HP laptop running Windows.

If that doesn't work, a clean start is likely in order.

You'll need an OS X install DVD and an external drive (or an appropriately bootable external drive with an OS X install image) to re-install OS X.

Once your OS is reinstalled, you can re-BootCamp the MB Air.