Ads by DNS Unblocker keep popping up all the time:
DNS Unblocker is a pesky adware that may generate a lot of pop-up ads on your browsers including Google Chrome, IE, Mozilla Firefox, Safari, etc. After the computer being attacked by DNS Unblocker, your browser together with system settings will be changed by this nasty bug. Every time, you open a new tab, DNS Unblocker pops up to hijack your browser.