Why Does My Computer Auto Restart On Shutdown

Have unchecked the ‘automatically restart box’ in System Failure Section.

Have taken the covers off and vacuumed and blown all dust out.

Have tried running in Safe Mode.

Have unchecked all the items in Startup, in MSCONFIG.

All of these items have been suggested in other posts, but none of them has worked for me. Would be very grateful if someone could help. Thanks!