Я пытаюсь вернуть мой компьютер к загрузке Windows 10, введя следующее в
grub > :
chainloader (hd0,gpt2)/EFI/Microsoft/Boot/bootmgfw.efi grub>boot
неверную команду, синтаксическая ошибка
Куда я иду?
If all is well you should see the Windows partition in the grub bootloader. This question seems to be a xy-problem. Why did you have to issue the command in the first place?
From there you could select the partition and windows starts... If that works you could - if you wish - configure your grub to start the windows partition by default- but that's another question.
If you do not see that windows partition you might have to setup grub again. In this case you should observe the output of the installation process and find a clue why it didn't work. You could edit your question and paste the result of the installation process there.