New iMac G5--can't get past "Pick a language" screen

The manual for my new iMac G5 says "The first time you turn on your
iMac G5, Setup Assistant starts." This did not happen for me. I turned
on my iMac G5, it opened the screen for choosing a language with "Use
English for the main language" highlighted, and I can go no further.
Mouse moves the cursor but cursor can't seem to do anything. I push the
arrow to go to the next screen, and nothing happens. I don't see
anything to do but unplug the machine.
Help appreciated. Thanks. T-L

 

That happens after installation of the system - it is possible that the
wording is imprecise there; I don't remeber, to be honest. But you
haven't gotten that far yet.

Did you actively select a language by pushing the language you want in
the list? Be sure one is selected and then click the arrow.

I feel pretty sure there is something you are overlooking!
If not, it sounds like a hardware fault with the mouse.

HTH - if it helps...

 

This turned out to be the case, as you suspected. I was not aware that
this new mouse has different sensitivities depending on where it is
pushed. When I pushed on the left side of the mouse, I was able to
click properly on the Continue button and proceed. Thx for help. T-L

 

Ah, you're using Apple's Mighty Mouse, it seems. It's a multi-button
mouse; the top to the left and right of the scroll ball are different
buttons; the two buttons on the side are electronically the same, so are
the third button, and the ball itself is a fourth button.