friends i had the same issue with windows(O.S) just remove all unwanted toolbars and unwanted softwares and than check for virus and malware . make sure you remove any unwanted 3rd party program before you run antivirus. get the windows updated for more contact windows http://goo.gl/cQqCDb and i am sure this will help
dell is most trusted brand . i so would suggest you to remove ad extension and untrusted bars and make sure you reset your browser. and remove the unwanted programs from computer . thanks this may help thanks
Download Google Chrome browse, it will automatically block all pop-up's. Or Download malwarebytes and superantispyware and scan your whole system with both of those programs until it comes up with no results and is clean. I highly recommend installing an antivirus software program.
some programs you have installed intentionally or unwittingly you should uninstall that program if you are not using. turn on the free Windows Defender or if you have any antivirus then scan your full computer. and also delete junk and temporary files.
Hope this helps! Do reply with results.