To enable the ability of modifying settings of 'CertSrv Request':
1. Open Register Editor to 'HKEY_LOCAL_MACHINE\SOFTWARE\Classes\AppID\{long numbers}'
2. Right click the {long numbers} key (AppID of Certsrv Request), choose permission.
3. Take the ownership to Administrators. Then grant the Administrators 'full control' permission.
4. Restart the dcomcnfg.
Then you can grant the full control permission to your account.
K