DNS Unblocker Removal Help - Guide to Completely Get Rid of DNS Unblocker

I have recently obtained this virus called DNS Unblocker and it's bugging the crap out of me. I went through my files and extensions and nothing showed up. So I went and got a virus remover (Avast), and it found a few viruses and removed them but DNS Unblocker is still there. Can anyone help?

Get more information about DNS Unblocker:

DNS Unblocker is designed specifically to make money and is classified as a nasty adware. Once getting into the target system, DNS Unblocker displays pop-ups and advertisements everywhere. DNS Unblocker may generate web traffic, collect sales leads for other dubious sites, and display unwanted ads and sponsored links within your web browser. When you are searching information from the search engine, suddenly, you are redirected to other dubious websites.