boot - I deleted Ubuntu and accidentally deleted Grub with it. Other OS's aren't booting now. How do I fix this?

I was running a dual-booted Ubuntu/Windows 8.1 PC. I deleted my Ubuntu partition so I could install Arch, but in doing so I also accidentally messed up Grub and deleted my Windows EFI partition. I spent some time trying to restore the EFI partition, but I'm wondering if I could fix all of this by reinstalling Grub. Is reinstalling Ubuntu the easiest way to fix this? I can't reformat the drive because I have important work there that I can't lose.

I'm at school right now so I won't be able to post any logs until around 3:30 CST. Any advice would be greatly appreciated.

Edit: My problem extends beyond deleting Ubuntu. I accidentally messed up my windows filesystem and now it won't boot. It starts up and says there is no OS. I believe the best way to fix this would be to reinstall Grub but I need some confirmation of this.