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Awesome guide, thanks a lot! Since the WinXP is just a single exe file, UnrarX cannot extract it. Any idea to fix this besides extracting it on a Windows computer?
Hackers don't search for easy solutions ;) You can use any hex editor to cut the PE file: just cut from the beginning to the point where the Rar! signature starts and rename the extension to .rar.
Edit: There is no "Rar!" in Windows_XP_IE6.exe :(