I have a question about creating new wallet addresses.

Is it possible to create a new wallet.dat file with an address (wallet.dat file has been removed) when the computer is temporarily not connected with the internet?

Ifso:
1. Then there might be a change (probably not be expressed in figures) that somewhere else on the world the same address is being created?
2. When will this new address be available / or is it directly available to receive any coins before/without it has been connected to the internet?

It's not quite clear to me how I should understand this.

I'm sorry for that 

Thanks in advance for your answers.