Being a pure bred Windows acolyte and Mac OS virgin means that i'm unfamiliar as to the disk/file manipulation methods file used in Mac OS X on Windows files and directorys.. I'm not sure whether you can even load windows registry hives from a Mac OS X file system...
In the second link (password reset via the registry) you just need to use a Windows 7 System Repair Disc to boot from. You sure you can't procure that somehow?
I'll bring back some help, just hold on tight!