I used 7 64-bit and it was an issue getting it installed, I cheated, I installed on a PC, shutdown and moved the drive.
I never share the same drive with both. I use independent drives.
You should not be using anything older than BC 3.04 though, NOT 1.3 which was BETA for XP and maybe Vista.
32-bit: you get 1.9GB RAM use, so use 64-bit if possible.
I now have Windows 8 Pro 64-bit on mine. But I did have trouble with 7300 and it is a junk card anyway so replace and upgrade to something decent. GTX 460 or Apple 5770. Something.
I had BSOD with the 7300GT. And mine even though from Aug 2006, original, the firmware for 7300 was not applicable either.
When booting normall Windows 7 CD it is displaying some boot menu, and stops I know it is a problem with this Mac.
Do installation of WIndows 7 x64 and Boot Camp 4 will solve my problem?
How can I create this working WIndows 7 x64 DVD?
Did You had this problem with 16-colours and 800x600 resolution?
I can't boungt a new graphics. Officially I cant even open this Mac case
normally you install a driver from nvidia and make sure it supports 7300 series.
you really should junk it. the 7300 and the idea of using Mac Pro 1,1 to install x64
use a VM
there are tutorials on Imgburn and Boot Camp
Boot Camp 3 drivers are what you need. Or 4 but it won't help installing.
Select CD: 1 or 2
that is issue with EFI32 and Windows 64-bit