You can check if your system is infected by typing
dns-ok.us in your url tab. if a graphic with a green background appears, it’s safe. If the background is red , your pc is infected.
How to remove malware from your system?
DNSchanger is a malware also called Alureon that redirect internte traffic through rough DNS servers controlled by criminals according to FBI. DNS servers are computer switchboardsthat direct webtraffic.
The best option will be at show your pc to a professional. There are also tools available online to remove the malware.
Some of the removal tools: