It just works - my 2012 13" MBA is acting up - help me, pppplease

2012 MBA (latest model before Haswell refresh I believe).

Been bootcamping Windows 7 on it for the better part of a year now without any real issues after I got the initial kinks worked out.

About a week ago I was reading up on Widi and trying to figure out if the chipset I had would support it. During this process I saw there was a new Iris driver, so I went ahead and updated.

Post driver update it appeared that some of the other bootcamp things had borked themselves (back-lit keyboard permanently off, f-keys normal Windows operation, etc).

NBD, I went ahead and reinstalled the bootcamp drivers, using the latest version provided by Apple. After that, all seemed at peace with the world.

But it wasn't. The change was subtle but persistent, the CPU fan ramps up, and gets louder and louder until it's painfully loud. It does this over the course of an hour or so.

Some quick Googling suggested that updating OSX could fix this - I don't know how - but maybe that update includes some firmware or bios change that bootcamp relies on? I don't know.

So I go to update OSX. This is where stuff really hits the fan. The update borked itself and now loading into OSX greets me with a white screen of death. I can't seem to restore or do anything to OSX. Windows continues to operate fine, with exception to the annoying fan, but OSX is shot.

Any suggestions?