Go to a CLEAN computer, download MALWAREBYTES, save it to a flash drive. Boot the sick system to safe mode, install and run MWB (from FD) see if that doesn't do the trick.
My husband was web browsing and clicked on the link for Overstock. Instead of getting overstock he got a pop-up that said Spyware Protection. It started to run a scan and gave him the option to stop scan, scan, or purchase protection. He has McAfee and it won't allow him to open it or to open the browser. Can this be removed? If so, how?