Need help performing a clean install with a dual boot

You guys were right - I should have performed a clean install (if you remember).

I have a 1TB drive with a messed up Windows 10 FCU. I am only using about 250GB - so I have 750GB in which to install a clean version of Windows 10. I need instructions on how to partition my drive (about two equal partitions). I want to keep my messed up version of Windows so I can keep working. Meanwhile, I will perform the clean install on the other partition and install all my apps as time allows. PS: All my data is on a separate drive. When I'm done installing my apps on the clean install, I will want to delete the messed up version of Windows 10 and the dual boot- to be left with the clean install only with no problems. I use EaseUS Partition Manager & EasyBCD. Will you folks help me out doing this? Thank you...........

1. Open Disk Management by typing diskmgmt.msc into Start Menu.

2. Shrink partition by right clicking the partition you want to shrink.

3. After you have shrink a partition you will have a unallocated volume you will install Windows 10 on this unallocated volume.

If you are dual booting Windows 10 you don't need EasyBCD.

4. After you have finish with setting up new Windows 10 open the System Configuration by typing msconfig into Start Menu.

5. From Boot tab select new Windows 10 boot entry and click "Set as default" button.

6. From Boot tab select old Windows 10 and click Delete button.

7. Open Disk Management by typing diskmgmt.msc into Start Menu.

8. Right click old Windows 10 partition and delete the partition.

There are problems with what you want to do if you try and do a clean install on a drive with windows on it its likley it will put boot files on the wrong drive It may complain about activating. Can you post a screenshot from diskmangmentso we can see if your running gpt,mbr or eufi

Sorry it has taken so long - I'm not that well. A<br>Here's the Disk Management screenshot.

You might prefer to use MiniTool Partition Wizard Free to modify the partitions.

I want to clean install Windows 7 on a SSD currently having Windows 10. I understand you just shrink the main C: partition to create sufficient free space for the new OS then clean install the new OS in the unallocated disk space using the custom install option. Windows setup should then sort out the boot options and display a new boot menu for you to select which OS to use.

It sounds like there may be a disadvantage to my system if I do what you say. Please explain. I want to get this right before I install a second version of Windows 10. I'd hate to have problems later.