How to boot a win 7 hard drive that was in Ubuntu system?

[Jim]

I have a system that has 3 hard drives. Ubuntu 12.04, Ubuntu 14.04 & 
Windows 7. Haven't used Win 7 for a long time, but now I have a sudden 
need to do so.

When I booted win 7 it installed updates and failed on SP 1. Googling 
says a possible cause is SP 1 can't deal with grub. A suggested solution 
was to unplug the linux drives and boot with just windows present. When 
I try that I get the message: BOOTMGR is missing.

All the solutions I have found require that I use a Win 7 install disk 
to fix it, I didn't get one when I bought this system many years ago. 
What do I need to do to get win 7 to boot without the drives containing 
Ubuntu present?

Thanks,  Jim