I am unsure why the 3,2 key combo is not working for some but it does work for me. Some users on the apple forums have issues with the 2011 MBA & Lion but others do not. I would suggest trying again if you don't like terminal or messing with com.apple.boot.plist. Try holding 3 & 2 immediately after clicking restart and holding until you see your desktop. Either way though as long as you get into 32-bit mode it should work for now.
As for USB, there should be no issues. The USB and network modules are separate and only the networking kext fails to load. I just tested with my built in SD card slot and a SanDisk flash drive and they both work as in Lion.
I might try to mess around to get networking working tomorrow while the parallels team is working. In the Lion DP it took them a while to get anything out so I'm not so optimistic for a quick fix from them.
This, most likely, has nothing to do with Parallels and is probably a Windows issue. Once a VM is started it is up to Windows to boot succesfully. The Parallels installer probably just crashed (it happens) and left a driver halfway installed which when Windows tries to load on booting causes a BSOD. Try Windows safe mode(F8 on startup) to uninstall a driver or reinstall Parallels Tools.
P.S. all my testing for now is done on a 2010 MBA.
Last edited: Feb 18, 2012