One annoying thing about modern OEM systems is that they come with "recovery discs" instead of a regular Windows installation. On Vista recovery discs from HP (and probably others), those files are stored as .WIM files. I was initially under the assumption that these were somehow encrypted to protect them from tampering, as my initial attempts to open them had failed, but the reality is that they are spanned WIM volumes and can be reconstructed to a whole WIM image file, then mounted using imagex.exe.