So i recently installed Win10 64bit (guess why) on my long serving Win 7 system and intended to keep both OS in a dual boot configuration. There is a tutorial which told me this is completely possible and Win10 recognizes a Win7 system at startup and asks which one to boot.
I have 2 SSDs, created an unpartitioned space on one of them and, using partition wizard, and switched its partition grid to GPT, installed Win10 and this works. But: Win10 doesnt find Win7 at bootup as intended. To get into Win7, I had to manually change the boot HDD in BIOS setup.
After a bit of switching around, the Win7 OS doesnt boot anymore. Selecting to boot from "Windows boot manager" in BIOS brings me to Win10. But when i try to manually select the Win7 SSD after that, i am only being shown a white blinking cursor and nothing happens after that.

So does anyone have an idea how to get my Win7 system back, or to make the windows boot selector recognize that installation?

Edited August 29, 20205 yr by Soulflight

Sorry I can't help you but was wondering if you got this resolved?

I have 2 SSD's and either boot to one of the other depending on which i pick. 

https://neosmart.net/EasyBCD/

Jim

CYWG

I have both but not use the boot manager, just smash F11 and select the SSD I want to use then...

Yes. this is a known problem with Win10, it will rewrite the MBR. As the previous poster mentioned using EasyBCD is the quickest and easiest way to correct this. I have used this program with success and can recommend it.