Hi
Using BootCamp install windows 7 or 8 may not as easy as it thought if you have a new MacPro without DVD-ROM.
what you need
- two usb drives (one stored windows 7 or 8 drives, one stored windows 7 or 8 installation files. Both format to FAT32)
- windows 7 or 8 ISO
Before start BootCamp
1) download windows 7 or 8 ISO file
2) unzip the ISO file using 7zip or winzip to a temp folder
3) make your 4GB usb drive bootable and copy all installation files to the drive
How to Make a USB Bootable: 10 Steps (with Pictures) - wikiHow
launch BootCamp assistance
1) there are three option in the screen, the first option may disable. No worry, you don't need it. You only need the second option, download windows 7 drivers and stored it to another usb drive (about 870MB)
2) after you complete download the drives, you don't need BootCamp anymore.
3) go to Disk Utility and create another partition name it as BOOTCAMP and format it as FAT32
4) remove the drivers usb drive and plug the windows installation usb drive to MacPro
5) restart MacPro, press and hold on option key. It will let you select which partition to boot, than windows 7 or 8 will start installing...
Hope this will help