I had the same problem on Firefox and the solution is actually quite simple. Click on the Firefox tab in the upper left corner, go to Help>Troubleshooting Information, then select the Reset Firefox button on the right. That fixed the problem for me and hopefully for you as well. I would say you should try to do the same with other browsers if this is occuring on Chrome, IE, etc.
(note: I am using Firefox)
So it appears my computer is infected with a new strain of browser hijacker called 'searchiu.'
Whenever I open a new tab, it opens a browser under 'searchiu.'
Unlike previous incarnations (searchnu, searchqu, etc.), it doesn't appear in my add-ons, it didn't install as a new toolbar, Google is still set as my default search engine, and it doesn't appear under 'search providers' in my 'internet options' settings. And it doesn't show up when I run a scan via malwarebytes or Microsoft SE.
I don't know enough about software to go about deleting files in the operational folders of my computer.
Any suggestions on how to get rid of this sneaky SOB?