Blizzard's Warden Thwarted by Sony's DRM Rootkit
I love when people claim Linux is harder than Windows. "Oh, just maintain TWO Windows installations!" :)
It was actually my father who did this with NT4. I have no idea if it's still easy/possible to do with XP, as I use RH8 as my primary desktop (plus other computers with everything from RH7.3 to FC4), and the last Windows version I personally installed was 3.11 (not the For Workgroup version) on a P90, about 8 years ago.
But the point is still valid (about the 2 Windows installations). That way, you have all the rights you want on the "not booted" version, and all the power of running native software to examine/modify it, plus enough storage for all you want (which booting from a Windows CD doesn't always offer you, although I could be mistaken on that as I never used one).