It was G4 Sawtooth Mac which I upgraded with 1.5 GHz Gigadesigns processor. The upgrades were the latest for OS 10.4, however, 10.9 package was could not be installed. I do not remember exactly what those upgrades were. They were chosen when I clicked "Software upgrade". One of them was iTunes. The screen was gray with a spinning wheel and apple. I eventually called apple support, and the specialist suggested me to take a shift button procedure you were mentioning. Well, it did not work. So he suggested then to reinstall OS since I did not have anything on the hard drive. It worked and the connection with the Internet was set. I decided to download the smallest upgrade. It worked, but after rebooting there was no connection with internet. I called Verizon and they said that it was probably a computer problem. Now I am stuck with with this problem. It is strange: there is internet connection at the end of OS installation, then it disappears. Any idea what could be the problem?
Thank you,
Valery