Question Help!! Windows doesn't boot anymore

[Kyranky]

So i have 2 drives, a 500gb SSD, and a 1TB SSD. The SSD is my main drive. I recently installed the HDD as my SSD was getting low on space, and I was going to put mainly all my games on the HDD. This HDD came from another's computer, ans had Windows 10 on it. I did not intend on dual booting, however I recently booted into the HDD to check for any personal files and all that, of which there was none. So I shut the computer down normally, and booted back into the SSD.

However I was greeted with a blank screen and a blinking cursor.

So I booted back into the HDD, which instantly went into automatic repair. Then it threw automatic repair couldn't repair. And this is where I'm at now. No way of booting, at all.

I've noticed that when I don't have the HDD plugged in, there is no option for windows boot manager in the boot menu or bios. What's happened here? There I s an option for windows boot manager when I plug in the HDD, but that just does the automatic repair thing.

I many, many files and saves on that SSD.

What do I do?
and what even happened?

Any help would be GREATLY appreciated.

Thanks

 

[USAFRet]

Physically disconnect this alien HDD.

Power up.
What happens?

Also, what specific drives and motherboard are involved here?

 

[Kyranky]

Physically disconnect this alien HDD.

Power up.
What happens?

Also, what specific drives and motherboard are involved here?

Just a blank screen with a cursor. No splash screen, or any sign of windows at all.

The drives are:
SSD: Crutial BX500 2.5" 1000GB SATA SSD
HDD: Western Digital Cavier Blue 3.5" 500GB Internal Hard Disk

And my motherboard is a little old,
MSI H61M-P31/W8

Thank you for your reply.

 

[USAFRet]

Go into the BIOS and check the boot order.

 

[Kyranky]

Go into the BIOS and check the boot order.

The SSD is first. And windows boot manager doesn't show up.