How to change setting about Comodo DNS server

When installing the new CIS10 at one point you get the option to use Comodo DNS servers.
I do not remember if I unchecked this.
Where can I check/ change this?
Problem is I cannot update the virus database and I think it might be because I am on the Comodo server

Windows 7 / Vista - Manually Enabling or Disabling Comodo Secure DNS Service

Thanks - seems I was not on DNS server.
Could you also tell me if you would advise to use Comodo secure DNS server?
My provider here in Belgium is very good.
And if I have problems they help me.
To me it seems risky to use an unknown server