China DOS Union

(1) Under WINDOWS, I changed the value of the registry key:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\system\nodispcpl to 1 to disable opening Display Properties. How can I change the value of Nodispcpl to 0 under DOS? What are the exact steps?

(2) I already backed up the computer's registry and saved it on drive E. The registry backup file is: regbackup.reg . Now the computer cannot enter WINDOWS, and I suspect the registry is damaged. How can I import the regbackup.reg registry file under DOS mode to replace the current registry file? What are the exact steps?

Please, experts, answer. Thanks!!!

Use the scanreg/restore command and choose a time you want to restore to, and that will do it.

Use scanreg /restroe, this can restore the entire registry.
You can also use the method of importing a *.reg file, but this requires you to know the format of a *.reg file and write it yourself, or that you previously exported a *.reg file. If you have a *.reg file, you can use REGEDIT A.REG under pure DOS (assuming the name of the *.reg file is A.REG. If you haven't exported one before and don't know how to write one yourself, then you can use
regedit /e a.reg HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\system
to export the contents of the HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\system key, then use EDIT to modify it and import it again.

Can XP use it this way?