After starting up and running Firefox I get in the lower right screen an error box: Browser settings changed. An unknown change was detected on your browser search settings buttons. The accept or reject buttons do not work. Then when I close the program, it pops-up again after a few minutes! I ran Norton Antivirus, have run anti-malware, last version of Firefox loaded, but nothing helps. Please let me know how to stop this error message from popping up!