Currently, there are about 240 separate files that get modified by this pack. The pack comes with some nice extra´s, like 32bit icon support on Windows 2000! Vista sound and cursor schemes, custom boot screen, and its own wallpaper.
The pack uses ResHacker (best for scripting resource tasks) to change icons, bitmaps and some dialogs, to make it look like the new Microsoft Windows Vista.
The installer takes a sample of the file that has to be modified, and backs it up. Then it changes all the resources in the original file, those that are needed for the Vista look. When that´s done, it places it back into the system, and will reboot for the changes to take effect.
Vistapack has some other advantages like the Reloader. This little sub-program, runs on Windows start and checks if any files are changed. This can happen if you got a update from Microsoft, or have visited the Windows Update site. When it spots a changed file, it will "Reload" that file with the Vista resources again. So on your next reboot, that file is Vista style again. Good way of keeping your system in the Vista look and feel.