How completely remove a new Safari and re-install old?

I need to reinstall an Safari 5.1.1 Snow Leopard on my iMac 2.66 GHz Intel Core 2 Duo with 4 GB 1067 MHz DDR3 running OS 10.6.8. I clicked on a web site that said "does not support your browser." So I updated Safari, but when I tried to open it, I got the message "does not run on this operating system." I uninstalled the new Safari and downloaded Safari 5.1.1 Snow Leopard. When I tried to install it, I got the message, "Cannot install. A newer Safari is already installed." I went back and deleted every Safari folder, and tried again to install Safari 5.1.1 Snow Leopard. Same "cannot install. A newer Safari is already installed." I shut down and restarted. That removed the new Safari symbol from my dock, but I still got the same "A newer Safari is already installed."