I downloaded Ubuntu 12.10 on a CD, but I can't install it on my PC because it doesn't connect to the wireless internet. It doesn't even show the wireless option on the top right of the screen. System Settings doesn't open when I just try Ubuntu on the CD (without installing it). What should I do!??
It seems that your wireless adapter is not supported out of the box. Install your system using a wired connection, after that you can (let's hope) install the drivers for your wireless card.
Note: we can help just if you post the hardware details of your PC.