If anyone DOES ever hose a box completely, anyone with Microsoft's
TechNet access can get a Windows 7 DVD installer - which you can
easily put onto a Flash drive.  (That's my preferred method) - I found
a little utility to remove each disk from booting for only a certain
version of Windows 7 too, so it prompts for which 'Edition' to
install.  Have 32 and 64-bit ISO's for both, you'll need a product key
to go with it.  (You get 30 days to put it in if you don't have it
immediately)

Then you'll just need to dig out drivers for whatever Windows doesn't detect.