Check your browser/s delete all your history, cookies etc.

go to control panel, look in the programs and feautures box, check you do not have any programs you do not recognise.

go to the start menu, select the button for accessories, under this you will find a button saying system tools, click this go to system restore, go to the restore let it load, select a day when everything was fine from the list.

wait till it finishes and reboots.

after this download housecall, once you download it, run it and delete any dodgy things it finds.

after this do same again download cc cleaner and antimalware bytes, with both you will be prompted to use standard settings, don't alter settings unless you know what you are deleting.

back up registry if prompted.

then make sure you run each and follow guides to delete rubbish off the pc.

go to your browsers, select add ons, delete any add ons you installed by mistake, don;t recognise or dont use

especially babylon

restart your pc

hopefully it may help