Dear Rehman, Thank you for your comments. If hardware failure there will be no any alternative solutions. So, that’s why every IT infrastructure having additional Domain Controller. If you are having additional DC you can easily seize the fsmo roles. And one more solution if your hardware isn’t failure you can use Directory Services Restore Mode(DSRM) and you need to run you server in Maintenance mode. Using msconfig.exe select safe boot and select Active Directory Repair.
