Windows won't boot after installing Ubuntu?

Question

linux

Good evening everyone, I have to ask for help because I have been racking my brains all day how to start Windows.
I installed ubuntu 20.04 lts on the computer where Windows was installed, but fortunately there were 4 disks on the computer and there was a dozen (main) on disk C, eight on D - eight (did not use it), installed ubuntu on E after installation, both systems worked for a short time, but then something then it went wrong and Windows stopped starting, namely, before each inclusion in the GRUB bootloader, choosing the system, if you choose ubuntu, everything will be ok, if the following happens to Windows:
alternating one after another, then a black screen appears for a second and a return to grub, then preparation for automatic recovery and the inscription Choice of action on a blue background where if you start to continue (using Windows 10) nothing will work again and a hornbeam will appear, and if you press exit and use another OS when you choose Windows 8, the figure eight will start, please help, thanks in advance

Answer 1

Try to do bootloader recovery (MBR) Windows 10 from the link .

Answer 2

Method 1 (Correct)
If you have not wiped the boot partition with Windows, you can try from Ubuntu (terminal):

sudo add-apt-repository ppa:yannubuntu/boot-repair  
sudo apt update  
sudo apt install -y boot-repair && boot-repair

After launching Boot Repair, find and select Advanced Options-->Other Options-->Repair Windows Boot Files . The boot flag must be placed on the same partition where Ubuntu is installed. The partition on which Ubuntu is installed can be determined from the Disks application built into Ubuntu.
Method 2 (Wrong), but for emergency recovery will do.
Also from the Ubuntu terminal: Find chainloader +1
sudo nano /boot/grub/grub.cfg
near the end of the file and add ntldr /bootmgr on the next line

...
drivemap -s (hd0) ${root}
chainloader +1
ntldr /bootmgr
}
...

Answer 3

I would like to know what is wrong with this method, what does it affect?