Well, I sort of have a working Windows setup now.
My cMP is a 5,1.
You gave me an idea (or maybe I misunderstood you) in a few postings back: to do a fresh install of a MacOS
on a separate drive, then use Bootcamp there, the way it's supposed to be -to create a Windows partition on that same drive.
No, I don't
have to use MacOS 10.9, but I was thinking about some older software that I need to use, but thinking about it it's another story and I'm going to investigate if I can use that in a virtual machine type setup, ...later.
Anyway I ended up doing a reboot in recovery mode (hold CMD-R while booting) which allowed me to create a brand new MacOS 10.13 High Sierra on that separate drive (I realized that in addition to the MacOS version you can also see the startup drive's name when going to System preferences-Startup drive).
When that was done I booted into
that drive's MacoS 10.13 High Sierra and ran Bootcamp Assistant along with a Windows 7 installation DVD and a newly (FAT) formatted USB flash drive as instructed in Bootcamp. Everything fine so far. The computer rebooted into the Windows installer and when I got to the part which shows the various drives (where to install Windows?) I chose the "BOOTCAMP" drive followed by "Format". This resulted in an error message:
Windows is unable to install to the selection location. Error: 0x80300024
I looked this error message up online but couldn't find any clear explanation. But from one forum discussion I gathered that I should remove any unnecessary drives, so I powered off the Mac, removed all drives but the new one (with the new MacOS 10.13 along with Bootcamp), restarted and continued with the Windows installation. This time it worked and I booted fine into Windows.
Using it is another issue.... even just installing the Windows drivers for my HD-7950 was a pain. Constant complaints about permissions and unsigned files etc. I think I tried it 5 times before succeeding. There's a reason why I never went for PCs
Now I have a new problem: a blue screen of death when booting into Windows with this error message:
IRQL_NOT_LESS_OR_EQUAL
So I got thinking back to the installation (formatting) problems... hmmm.
Could it be that by removing all other drives the system refuses to start with my normal configuration? So I powered down, removed all other drives, rebooted and it worked.
What a pain! So now I have a cumbersome, but working system -hopefully I can sort out the GPU firmware stuff and reflash the card for getting a Mac EFI bootscreen, then forget about Windows
I think if I need to have Windows again I'll just install it on its own (on a separate drive without MacOS/Bootcamp) as I did last time, and without Brigadier or other attempts to install the Bootcamp add-ons. I'll settle with having to do a PRAM reset (CMD-ALT-P-R while booting) to get back into MacOS.