Healthy (Recovery Partition) and (EFI System Partition) on wrong drive.

You might want to try the following process. We've used it successfully to create an EFI System Partition on a GPT-partitioned drive that for one reason or another did not contain the EFI partition and thus was unbootable. We haven't used this procedure involving a situation precisely like the one you're experiencing but (hopefully!) it should work to create the EFI partition on your 250? GB boot drive which will become bootable after deleting the EFI partition from your 500 GB Disk 0.

But understand there are NO GUARANTEES HERE SO IF YOU DECIDE TO UNDERTAKE THIS PROCESS YOU DO SO AT YOUR OWN RISK. IF YOU DECIDE TO DO SO, ENSURE THAT BEFORE UNDERTAKING THIS PROCESS YOU FIRST CLONE THE CONTENTS OF YOUR C: DRIVE TO ANOTHER DRIVE SO THAT IN THE EVENT THE PROCESS FAILS AND YOU WIND UP WITH AN UNBOOTABLE SYSTEM YOU WILL HAVE THE MEANS, I.E.,THE RECIPIENT OF THE CLONE, TO RESTORE YOUR SYSTEM TO ITS PRIOR FUNCTIONAL STATE.

CAPICHE?

I assume you have at least a "passing acquaintance" with the DiskPart utility. If you don't, do a Google search on "using diskpart".

1. Access DiskPart.

2. list disk

3. select disk # (this is the disk where you want to add the EFI System partition - presumably Disk 2).

4. list partition

5. select partition 1 (the Windows OS - presumably Partition 1).

6. shrink desired=100
"DiskPart successfully shrunk the volume by: 100 MB"

7. create partition efi size=100
"DiskPart succeeded in creating the specified partition."

8. format quick fs=fat32
"DiskPart successfully formatted the volume."

9. assign letter=S
"DiskPart successfully assigned the drive letter or mount point."

10. Exit DiskPart

11. At command prompt...
bcdboot C:\windows /s S:
"Boot files successfully created."

12. Exit

13. Disconnect the 500 GB drive that presently contains the EFI System Partition from the system. DON'T delete any partitions or data at this time.

14. Boot ONLY with the 250 GB boot drive (you can include the 1 TB secondary drive) connected to determine if system boots to the OS and functions without any problems. If the system is COMPLETELY functional, connect the 500 GB HDD and delete the EFI System Partition from the drive. You'll probably need to use Diskpart to do so with the command "delete partition override" after selecting the partition.

15. Exit. You can also delete the Recovery partition.