Directions for installing Windows 7 64 on a 2006 Mac Pro w/fully functioning Bootcamp 3.x. Mostly for my own reference.
You'll need: 1. Windows Disc 2. Bootcamp Drivers (burned/downloaded/retail os x disc)
1. Run the Bootcamp Assistant and make your partition.
2. Insert Windows Disc
3. Note which drive bay your main OS X partition is located on.
4. Shutdown and remove OS X partition drive.
5. Boot w/ option and install Windows from disc.
6. Eject Windows Disc, insert Bootcamp disc (cd tray will be open) and shutdown.
7. Re-install OS X drive.
8. Reboot. Windows should load by default.
9. Find Bootcamp/Bootcamp64.msi and run via 'troubleshoot compatibility'. Reboot.
10. Using regedit find instances of 'ForceDisableJD' and replace string '00' with 'FF'.