Thank you very much for the excellent suggestion to download MalwareBytes for Mac. I was really apprehensive about downloading anything. I have a MacBookPro, late 2008, running 10.9.5, and until last month had virtually no issues. I was researching when I accidentally clicked on an ad instead of the 'next page' arrow. It's been a constant nightmare since then until I read your posts. I cleared cache, history, (after writing down every password for each website I use) and still it bullied its way into my laptop. I'm so glad I found your post.
I have a back up system for my Mac that I run, and I never take it off my desk. No one touches my Mac-
A few questions:
How often should the system be scanned?
Should I upgrade to a newer OS? I have Snow Leopard
Regards,
Dinah