Q: virus?

Please specify what exactly pop ups? Where and when it pop ups? My assumption it is adware symptoms. Can you please describe the issue in more detailed way. If your browser is bombarded with ads is it adware injection symptom.

Follow the instructions on this web page  in order to manually remove adware from your mac: https://support.apple.com/en-us/HT203987

You may also find adware removal guide on this page http://www.thesafemac.com/arg-identification/

If you do not want to remove adware manually use this anti malware tool in order to scan and remove it: https://www.malwarebytes.org/antimalware/mac/?utm_source=blog&utm_medium=social

If you see an alert you can't get rid of even after your browser restart:

1. Force Quit Safari .

  Press command + option + esc keys together at the same time.

  When Force Quit window appears, select  Safari .  Press Force Quit button at the bottom of the window.   

2. Relaunch Safari holding down the shift key.