Can I upgrade my Windows 7, 8.1 to Windows 11 for free?
You can indirectly upgrade the Windows 7, 8.1, to Windows 11 for free, but a direct one is not possible!
You can still use the Windows 7 or 8.1 product key to install / upgrade to Windows 10 for free. If you have updated to Windows 10, you can wait, sometime in early 2022 in Windows 10 you will be offered to update Windows 11 from here!
Yes, as long as you have multiple partitions and the PC passes the compatibility check, you can do so. However, you must have a valid and different license for both operating systems. You should prepare the hard drive before installation, or shortly after installation!