Verified answer

Sounds like a rootkit virus it can hijack your browser but without any windows open it can send you to advertising sites etc. Download "rootkit revealer" from Microsoft or Sysinternals and run it, These things can disable normal antiviruses and anti malware. Go to Task manager and under processes see if there is an oddnamed process sometimes just random letters and or numbers and end process. Then go to Start>run and type in msconfig and click OK, Look under the "startup" tab and uncheck the same process name if it appears there. The registry will need to be cleaned up but normal programs should be able to do that when you have disabled the rogue program.

These things can disable recognised anti-malware programs and system tools like task manager, so you may have to download process explorer or killprocess to stop the process, you need also to rename the malware bytes .exe file to, say for example, xxxx.exe or just copy it to the same folder when it will produce a copy called "copy of..." and run that. Instructions on the malwarebytes.org site