You don't install DNS... Comodo DNS just points to their servers http://www.comodo.com/secure-dns/
So either your dhcp server is handing that out to you, or you set it on your machine. Or the dns server you currently use (router) is pointing towards their dns servers 184.108.40.206 220.127.116.11
Why do you feel your using their dns?
What is the output of ipconfig /all on your machine - this will tell us where your pointing to for dns
If your pointing to a local dns - like you see from my ipconfig /all - then you will have to edit the config on that device not to use the comodo dns service.