net localgroup administrators adm_user /add

The user that is configured to run this scheduled task must have „Log on as a batch job” rights on the computer that hosts the exe you are launching. This can be configured on the local security policy of the computer that hosts the exe. You can change the policy (on the server hosting the exe) under

Administrative Tools → Local Security Policy → Local Policies → User Rights Assignment → Log On As Batch Job

bootrec.exe /rebuildbcd
bootrec.exe /fixmbr
bootrec.exe /fixboot