[SOLVED] MBR and GPT, Dual Boot, 2 HDDs, different windows

[Gebaben]

Hi there!

Currently I have windows 7 32-bit, and would like to have a windows 10 64 bit OS too on my PC. I definitely want to keep the win7 32 bit OS even if it is old, that is why I don't want a simple OS upgrade. I thought about dual booting on a single HDD, but with the split I've calculated that I would probably run out of space. So I started thinking about getting an another HDD and install win10 on it. The main problem is I am not sure about these MBR and GPT formats. Currently the HDD is MBR with UEFI BIOS and it is running fine. I don't know the new HDD should be MBR or GPT. I know the advantages of the GPT format but not sure if it would boot up with both OS.

Here some pictures of my BIOS settings:
https://ibb.co/zFvYf91

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Image smart hosted in ImgBB

ibb.co

https://ibb.co/G2xb4kx

I've read a post by @Colif on the forum that says: BIOS needs to be set up as Legacy only otherwise the WIn 10 installer will see PC is capable of running GPT drives, and if drive is blank, will format it as GPT whether you want it to or not.

Which settings exactly from the pictures above?
What other settings should I change in BIOS to get both OS working.
And which format should I choose for the new HDD to get the dual boot working fine? MBR or GBT?

About the next picture: I don't know if these yellow SATA6G and brown SATA3G makes difference when installing the new HDD.
https://ibb.co/5xRLLyh

My PC:
MB: ASUS H81m PLUS
HDD: Western Digital 500GB SATA 3.5 (wdc wd5000aakx-08u6a)
8 GB RAM
Intel i5 4460
Nvidia GT 730 2GB GDDR5

 

[Gebaben]

Ah I see. Alright thanks. Then I reenable it in services msc if it isn't necessary.

 

[Gebaben]

Update:

Hi!
So I've managed to install both OS and it seems it's working fine. Although I've got a problem:

The PC automatically boots into Win10. I've tried to change boot prioritiy in BIOS but the win7 disk doesn't show up. It appears below 'sata information' and 'boot menu' tab, but not in boot priority. I checked in advanced menu/boot where it lists boot priorities, but it only shows my win10 drive and the DVD rom. At the third option in the list it says 'Disabled'. I see the win7 drive among boot override settings also.

So I can boot into win7 but through bios. But I want it automically boot into win7 instead win10. What should I do?

 

[SkyNetRising]

So I can boot into win7 but through bios. But I want it automically boot into win7 instead win10. What should I do?

Can you show current screenshot from Disk Management?

 

[Gebaben]

Nevermind, I fixed it by entering BIOS/advanced mode/boot/Hard disk drive BBS priorities. Then I set up my win7 drive as the first. So it is working now.

Interesting that in bios priority only one drive show up besides the DVDrom, which is now the win7 drive. But that is not a problem because I can choose the win10 drive from boot menu anyway.

Thank you all for your help!