Windows 7: What do you suppose the Government uses ?

I would be surprised if the Government used MS other then for desktops, I suspect the servers and infrastructure are a unix/nix/foss set up. All OS have weaknesses, but the last three are the most stable and safe to use, in general.

I wouldn't surprise me if they still had OS/2 Warp on some systems. After all, the more you build onto something, the more locked in you are. But it's prolly on desktop stuff as you say.