Grub error, need help

Hi everyone!
I found a similiar thread, but i’m concerned my situation is more complicated. I hope not! :@
So, i found an old hard drive, and thought it would be amazing to install linux on a seperate hard drive and dual boot between Netrunner and Windows 7.
So i installed Netrunner, and right after that i wanted to boot into windows. I got this: error: no such device grub error.
I immediately went to bios and as my first boot device i put the old hard drive containing Netrunner. And that didn’t boot either.
So then i really freaked out. I disconntected the hard drive containing Netrunner. Still couldnt boot into windows.

What to do now? I found somewhere i need to make a bootable USB containing windows 7. and run repair mode.
I downloaded " startup disk creator" but seems as though i cant use my windows iso file with it. Is there a programe in linux i can make a bootable windows usb?
I still want to continue using windows 7, and the stuff i have on my primary hard drive is very important.
But if i resolve this issue, i still want to use the old drive i found for running netrunner.

Anyway…sorry i went on a babbling spree, but very anxious to fix this.
As you might have already thought, i am a complete noob lol.

Help! And thank you upfront.

First make sure that when you can boot into netrunner that all the data on the windows partition is still accessable.
This might be also a good point to do a backup of your important data if you not already did this.

Is there a particulary reason you can’t use the dvd of windows to restore the bootloader ?
I would at least try the Super Grub Disk [now called rescatux] ( ) which has a windows entry which allows you to ‘fix boot of Windows’(also called restore windows MBR).

Thankfully, i see my drives, and everything is there. I backep up some of it to another usb stick, but unfortunately dont have anywhere else to put anymore.
Problem is i dont have a cd/dvd drive. Don’t really use it anymore, so got rid of them over time.

I downladed the super grub disk, now i have to make a bootable usb ouf of it?

Yes exactly. If you don’t have a cd/dvd drive thats the only way to boot it.
You can try unetbootin or one of the other recommends methods described on the supergrubdisk site