How do I add windows 7 onto the preinstalled windows 10 through dual-booting?

[simonz93]

My PC came with windows 10. I don't want to get rid of it, but some games don't work well on windows 10 and I need windows 7.
All the guides I see online tell you how to dual-boot windows 10 when you already have windows 7 or 8, but not the other way around.
Is it doable? Is it difficult? Is it safe?
Thanks!

Edit: Thanks to both answerers. I actually have 2 drives, the win10 is on a SSD, and I have tons of space on my HDD.
The one concern I have though, is that I read that you're not supposed to install an older OS when you have a newer OS installed. Does this still apply if I were to install them on different hard drives?

Another question since I'm a noob in PC. If I were to remove the SDD containing the windows 10 files when I'm going to install win 7, how do I install win 7 without being able to turn on my PC (since windows is gone)? My PC doesn't have a DVD drive, so I can only use the digital win7 install package.

 

[mdsiu]

Free up disk space on your hard drive, then shrink your OS Volume using Disk Management and create another blank volume to install Windows 7 onto. Alternatively, install Windows 7 on another hard drive.

 

[reedo_43]

The easiest and safest way would be disconnect the drive, add a new drive and install Windows 7 on it. You could just use the F12 key to boot to whatever drive and os you wanted. I am sure there are ways to do it without buying a new drive but this way you know you wouldn't mess up your Windows 10 install.

 

[simonz93]

The easiest and safest way would be disconnect the drive, add a new drive and install Windows 7 on it. You could just use the F12 key to boot to whatever drive and os you wanted. I am sure there are ways to do it without buying a new drive but this way you know you wouldn't mess up your Windows 10 install.

I actually have 2 drives, the win10 is on a SSD, and I have tons of space on my HDD.
The one concern I have though, is that I read that you're not supposed to install an older OS when you have a newer OS installed. Does this still apply if I were to install them on different hard drives?

Another question since I'm a noob in PC. If I were to remove the SDD containing the windows 10 files when I'm going to install win 7, how do I install win 7 without being able to turn on my PC (since windows is gone)? My PC doesn't have a DVD drive, so I can only use the digital win7 install package.

 

[simonz93]

Free up disk space on your hard drive, then shrink your OS Volume using Disk Management and create another blank volume to install Windows 7 onto. Alternatively, install Windows 7 on another hard drive.

I actually have 2 drives, the win10 is on a SSD, and I have tons of space on my HDD.
The one concern I have though, is that I read that you're not supposed to install an older OS when you have a newer OS installed. Does this still apply if I were to install them on different hard drives?

Another question since I'm a noob in PC. If I were to remove the SDD containing the windows 10 files when I'm going to install win 7, how do I install win 7 without being able to turn on my PC (since windows is gone)? My PC doesn't have a DVD drive, so I can only use the digital win7 install package.

 

[reedo_43]

Pull the ssd, install the other drive and install 7 via usb. It will work as I have done it...

 

[simonz93]

Pull the ssd, install the other drive and install 7 via usb. It will work as I have done it...

So if I pull out the SSD, I can still install something from the USB without having an active OS? So I don't need to go into my computer and open the USB?

 

[USAFRet]

Do you have a valid WIn 7 license and install media?

 

[simonz93]

Do you have a valid WIn 7 license and install media?

No I don't have anything for win7. I'm looking to buy it but I can't find it anywhere.

I've never installed an OS before (they always came with the PC I bought). So I actually have no idea how it should work, like what the differences are between the license, the key, the actual product, etc...