Uninstall Avira free Antivirus

PLEASE!! can someone tell me how to uninstall and completely remove "Avira Free Antivirus" from my PC?? Have already uninstalled w/ "powerful uninstall" from Add/Remove Programs....and tried to remove w/ Kaspersky Total Security, Glary Utilities, Iobit Uninstaller and permissions won't allow any of the above to remove "leftovers" which is still basically ALL of Avira w/ popups constantly on websites and desktop....It's like a plague!! and a virus in itself. Avira website doesn't offer an uninstall and community forum doesn't seem to have any answers for problem either....

Any help would be greatly appreciated!!