firefox "not supported by architecture"

I had a working version of firefox on my G4 but I could not use the advanced g-mail features (type size and style italic, etc.) The g-mail page tells me I must upgrade the browser. I have tried to install Google chrome but I get a message "not supported by this architecture. I have tried re-installing firefox but I get the same message? What is the secret?

Firefox (any more) and Chrome do not support the PPC architecture. A G4 is a PPC processor so you're stuck with older versions of browsers (or in the case of Chrome, you can't use any version since it's only ever been Intel only).

You can get TenFourFox which takes the ESR (extended support releases) and builds them for PPC machines. Currently, the ESR release of Firefox is version 10 so if you get TenFourFox 10, you'd be running the same software you'd get with Firefox 10.