Adware is type of malware that can cause issues for your computer. As already mentioned above, the reason for this is adware.
To answer why this happens, you need to understand what causes the automatic opening of new windows (ad,new tab). According to cyber security researchers, most users whose computers were infected with adware virus, ask to help them solve one and the same problem that sounds like Everytime i click something it opens a new tab (ad, new window).
