Windows 7 & 10 how to make them friends

Solution 1:

The reason is that Windows 10 installation media boots in EFI mode by default and demands GPT partition table for your disk. You should force the installation media to boot in MBR mode.

1. Call the boot menu when you computer starts (the list of boot menu keys for the brands);
2. Make sure that you select non-EFI (MBR / Legacy) option for you Windows 10 installation media.

You might need to disable EFI-boot in your UEFI/BIOS.

P.S. You can always bypass the windows PE problems (e.g. Win 11 incompatible PC) by manually extracting OS to a new partition with tools like imagex (gimagex) or dism:

A. Easy one (using your current old Windows):

1. Boot to your into current Win OS;
2. Create a new NTFS partition and mount it;
3. List the available Windows images in install.wim (install.esd) using GImageX (the easiest but doesn't support ESD) or using DISM;
4. GImageX Apply or DISM Apply the desired image to the created new partition;
5. Use EasyBCD (there's a free version) to add the new boot record

B. Directly from Win PE (Windows installation media). Don't run the bcdboot if you want to add the second OS. For dualboot use rebuildbcd instead. Here is the manual with screenhots. TL;DR:

1. Press Shift+F10 directly from Win 10 PE to call the cmd;
2. Create a new NTFS partition and mount it (use diskpart and format);
3. = Step A.3. (you can pre-copy GImageX to USB);
4. = Step A.4.;
5. run bootrec /rebuildbcd to add the new OS to the boot menu.