Cannot get Mac Pro 2008 to boot

The old drive has windows only, so it doesn't have a viable OS on it to run a recovery partition. Trust me, I wish it would have been that easy. I need an enclosure kit bc I can't put the drives into the Mac and install anything since there is no os to do so. I can't target disk it bc I don't have an adapter for firewire and that is the only kind this supports. I used the enclosure kit on the SSD and verified that the OS is bootable via my MBP which I stated above.

Its basically boiling down to run to an apple store and use their netboot server to install a correct image assuming that the needed drivers for this model were not properly put into the installer since I kinda ripped it out of an official image, or the newer drives are not compatible with the system and the project is basically scrapped.

Thats my guess right now, since I took the installer out of the app and made a bootable version. I just really didn't want to take it up to an apple store since its kind of a pain to carry. They have images for all models on their netboot servers even though these are considered vintage.

The drive isn't dead but its an old one and I don't have an enclosure kit that can power it to attempt the process with it.

Nope, no installer dvd but I don't want to pay 20 bucks for it since I can just go to the store.

Le sigh, looks like im going to the apple store.

Thanks for the reply!

Im aware of that, I should probably mention that I am an Apple certified Mac tech and have been for 8 years. My point stands that I have ZERO drives that have an apple recovery partition on them. The current functional drive was wiped and only has a windows image on it. No Mac software whatsoever. The new drives that I purchased, one an ssd and one is a 1tb seagate barracuda, I have imaged with a bootable El cap installer that was pulled out of the El Cap install app from the apple support page. I made it bootable, and verified that it was bootable with my MBP. Please see original post for the rest of the steps that I took.

The whole issue is that a bootable drive (verified) is showing in option boot on the Mac Pro. The recovery partition on that bootable drive shows on the Mac Pro. The actual installer on my bootable external shows on the Mac Pro. HOWEVER when I select any of those options, I am met with a persistent grey screen. No apple logo, nothing at all. If I don't option boot I am met with only a flashing folder, signifying no bootable volumes available.

At this point I am wondering if it is an issue with the installer since I used my MBP to create it and some needed drivers for the Mac Pro were not moved or integrated into it (why it works on my MBP and not the Mac Pro) or simply an incompatibility with the hardware in the newer drives. Since I do not have the hardware needed to wipe a 3.5 in drive (powered enclosure) I cannot test this theory. I am aware of the multiple drive bays in the Mac, since that was the point of being a media server and the reason I have multiple drives for it. The problem is that I cannot get it to boot to anything other than the Windows image (ONLY WINDOWS ON THAT DRIVE it is not a bootcamp and Mac drive, the Mac partition has been completely nuked and there is only one partition on the drive. It was wiped and stamped via deploy studio with a windows partition only)

Fair point, my wording was not appropriate but regardless I'm pretty sure that everything else I have explained gives rise to the assumption that I know what I'm talking about. I didn't think that I would have to be that careful considering I have explained in great detail that I am met with a flashing folder despite there being a bootable volume visible on option boot. But alas, all you have to contribute at this point is pointing out errors in my wording. Especially given my previous lengthy explanation that reiterated several previously mentioned points. Please either contribute something useful or refrain from commenting.

Would that cause the issue even though its seeing the drives? They show up in option boot as bootable volumes