This is from dictation.
Here in California it's time for me to go to bed. So I am going to do this with the voice dictation because I am a very slow typist and I have a hard time cracking my spelling errors. So any errors you see in this dictation are from the voice recognition software.
First of all, you are using Windows 7 64-bit and that means you're already off to a good start. Windows 7 64-bit has no trouble dealing with a GPT partition scheme. Actually, it can go either way with no problem. So you don't need to pay much attention to what I had to say about the GPT issue.
The proper sequence for putting Windows 10 and Windows 7 on the same computer is to start with Windows 7, which you already have. You need open up some disk space and your screenshot shows that you have two discs labeled disk 0 and disk 1. Obviously, the system boots up from the desk zero. Here's what you can do:
Make space on disk 1, which is the second disc in your system. You can use a tool like the Mini Tool partition Wizard to open up some free space at the beginning of the disk. Normally one would put them operating system at the beginning or outer edge of the disc and not on the inside. However, it will work either way. The Mimi-Tool partition Wizard will allow you to move the partition in either direction either to the left or to the right. Moving a partition to the right will free up some unused space at the beginning of the drive.
You can install Windows 7 on the second drive in your system and it will automatically modify the boot loader that is on disk 0, the first driving your system. I think you said You had Vista t on your system. You can either install Windows 7 on top of the other operating system or you can choose to install Windows 7 on the second drive.(Or the first drive, if you wish.)
Windows 7 will work perfectly well with the partition of 80 GB, and it works quite well even with much less. You should make sure that you have Windows 7 up and running first before you attempt to install Windows 10.
Again, you must have some space available to install Windows 10. Windows 10 can be installed almost anywhere you want to on the disk, but there is a preference to install it near the beginning of the disk if possible.
Once you have a suitable amount of space open up you can shut down the machine and reboot with your boot media that has the installation program for Windows 10.
Bear in mind that during the installation process the disk drives may not be correctly identified by drive letter. So you should have some other way to identify which partition is which. Using appropriate Label Names helps a lot. Also, the size of the partition can be helpful, but it's not always accurate. One utility might show that you have an 80 GB partition, but another utility mycologist 79.5 GB partition. That's a common problem and can cause confusion. That is why you want to use labels instead of depending just on the drive letter or the size of the partition.
I assume you have backups of any important data you need. The many to partition Wizard ours works good for me, but there's always the possibility that you could damage the partition it already has data on it, so proceed with caution.
I am not sure of what you're particular scheme is, but you may wish to have all your operating systems on the first driving your system. The work if there's enough drive space for each operating system. I found for my own experience that you can allocate as little as 40 GB to any the current Windows operating systems and it will install just fine. The trick then is to put. Library's of photos, videos and music onto one of your other drives and identified them as your libraries for the user that you normally use. This is one way to take full advantage of the disk space you have and yet have several operating systems on one huge hard drive. Done properly, you could share the libraries across more than one operating system in most cases. It is more of a hassle when using an older operating system like Windows XP.
If you restrict yourself to using just Windows 7 64-bit and Windows 10 a version, you shouldn't have any foreseeable problems with disk management.
I hope this of the some help to you. I need to get to bed now
End of dictation.
