Hello & Welcome to JustAnswer.
Thank you for your question. I will do my best to assist you.
May i connect with you remotely to troubleshoot the issue directly? Thanks
Since you've already tried emptying cache and cookies and that didn't solve the problem, i will have to see the issue to be able to troubleshoot it further. However, if you still want to be instructed then i will have to open the question to other experts. Let me know.
Click on the link below and it will automatically download Malwarebytes Anti-Malware for Mac, open it and select Scan:http://tiny.cc/fixmalwareIt will scan for malware and then give you the option to remove it. Then restart and run it again until you get no malware detected.