DNS Unlocker is an adware bundled within the free software from Cnet, Softonic or other similar web sites. So, on first step, open Control panel, then Uninstall a program, and uninstall this “free” software, all unused and unknown software. Next, download AdwCleaner and Malwarebytes antimalware from links below. Both are free.
AdwCleaner by Xplode from http://www.myantispyware.com/download/adwcleaner
MalwareBytes Anti-Malware from http://www.myantispyware.com/download/malwarebytes-anti-malware
Close all other applications and double-click AdwCleaner. Once this tool is started, click the Scan button to run a scan process. After the scan finishes click Clean button.
Next, run mbam-setup to start the installation of Malwarebytes Anti-Malware. It will open the Malwarebytes Anti-Malware Setup Wizard. Follow the prompts. When the installation is done, click to Scan now to perform a system scan. When the scan has completed, click on the Remove Selected button.
If you are still having troubles with the DNS Unlocker ads, then you need to reset your browser to default settings. Use the instructions:
How to reset Internet Explorer http://www.myantispyware.com/2016/03/07/how-to-reset-internet-explorer-settings-to-default/
How to reset Mozilla Firefox http://www.myantispyware.com/2016/02/07/how-to-reset-mozilla-firefox-settings-to-default/
How to reset Google Chrome http://www.myantispyware.com/2016/01/06/how-to-reset-google-chrome-settings-to-default/