Safari stuck on macsystemalerts.com warning.
My Safari has been taken over by a webpage, macsystemalerts.com and wants me to phone them at 800-680-4131. The message seems to imply that this is apple support, but I think it is bogus. How can I get rid of the alert and us Safari again? I'm using Yosemite.
MacBook Pro (15-inch Late 2011), Mac OS X (10.4.1)