Can I blast away EFI OS on second drive without bad Juju?

Disk 1 is the Windows 7 boot drive, which is MBR
Disk 0 is the secondary 1TB drive, which is GPT the partitions are: files, Windows 8 installer partition, bunch of UEFI partitions, then the Windows 8 boot partition.

The bootloaders are completely independent of each other, with the Win7 booting by selecting the disk and Win8 by selecting a "Windows Boot" option in the BIOS/EFI boot menu.

My question IS: can I blast away all of the other partitions on Disk 0 (except for the files one) without borking anything? and will that remove the "Windows Boot" option in the boot menu?

thanks.

So you want to boot into disk 1 and then simply use the other disk for storage?

Pretty much. To the bset of my knowledge the bootloaders are completely isolated, but I am unsure how the new boot menu option in the BIOS was created. Did the Windows installer actually added itself to the EfI's memory chip, or is the EFI finding the boot partition on the disk on bootup?

Yes they're isolated. The efi looking interface you're referring to is just a part of windows 8. They finally got rid of all those DOS era menus (white text on a black background) in order to make it look more user friendly. Like you, I tried the windows 8 preview as a dual boot option and eventually grew tired of it and decided to remove it. I can confirm that after you remove the installation of 8, the new menu types will go away with it and you will have a normal installation of 7. I would also make sure that you unmark the data only drive as active after you uninstall 8 from it just to be sure windows doesn't attempt to boot from it.

Unplug Disk 0 with the unwanted OS and boot partitions, swap its data cable to Disk1 Win7, set as HD to boot first in BIOS setup. Then test that it boots OK on its own, which it should since it's System Reserved boot partition remains System Active.

If so you can plug back in the other drive to Disk1 cable, delete the unwanted partitions in Disk Management or if it refuses by using Diskpart "Delete Partition Override" command after bringing the partition into focus with Diskpart.

@gregrocker. The SSD is using the first SATA and is set as the first boot drive. The hard drive didn't become Disk 0 until after I converted it to gpt.

@emaraszek not sure we are on the same page. My mothrboards bootstrap interface is IDENTICAL to standard BIOS interfaces, presumably because it's a low end model. I'm referring to that, since installing Windows 8 on the second drive, there is a new entry in my motherboard's boot menu/boot ovverride menu.

OK, so test the Win7 HD by itself set first to boot to see if it boots.

If so, plug back in the other HD to delete the unwanted partitions as given earlier.

I'm referring to the new style of clickable boot menus that appear in windows 8, which is what it sounded like you were referring to in your original post. I'm not sure if you're now referring to BIOS boot menus or windows boot menus. A windows boot menu may appear if, for example, you shut down your computer the wrong way, have two operating systems loaded on the same disk, etc. This is the menu that will offer options such as safe mode and recovery. The BIOS boot menu would be something that appears if, for example, you repeatedly hit F12 (standard on Dell PCs) when you first power up the machine. This will give you the option to boot from a hard drive, optical drive, USB, network boot, etc. Could you clarify whether the menus you're referring to are BIOS menus or windows menus? I've just never seen a BIOS menu call anything "windows boot" which leads me to believe you're actually talking about a windows boot menu. If that's the case, the windows 8 boot menus are the ones that are efi-esque (clickable), while the windows 7 menus are white text on a black background and are keyboard navigable only.

At any rate, there should be no reason to unplug any drives during this process especially since these installations are on two separate physical drives and not just separate partitions. Once you get back to me on these menus I can give you more specific advice depending on your unique setup.

If you don't first unplug the unwanted OS HD to test if Win7 will boot on its own then you will not know this for sure until after the unwanted OS/boot partitions are deleted on the Win8 disk, possibly requiring emergency repairs from Win7 DVD or System Repair CD with the Win8 HD unplugged.

We were specifically told that the boot loaders are isolated from each other and are located on two separate disks. Hence there is no relation between the installations and no need to physically change anything