MacKeeper messages / popups
Hi: Today I accidentally clicked a .dmg file which had automatically appeared in my downloads folder. Since then, I'm getting far too many messages to 'clean my Mac / your Mac has a virus' (much more than prior to clicking this .dmg file). Can anyone offer any advice?
I'm using an iMac (Retina 5k, 27inch, 2017) with MacOS Sierra. I cannot go any later with the OS or my older Adobe Software won't run.
Many thanks in advance.
iMac Pro