Now here is my situation, I have a network with internet connection and another without internet both networks using different switches (one switch for each network) , now how can I connect the two networks and share internet on both the networks ?

Daisy chain the switches

Now here is my situation, I have a network with internet connection and another without internet both networks using different switches (one switch for each network) , now how can I connect the two networks and share internet on both the networks ?
Please be explicit what excatly you want to do all with your existing infrastructure like which OS & ISP you are working with. What are your IP range etc etc..

That would help us to understand the scenario and provide the best solution.

Thanks, should work :)

Just use one switch to connect the two together and connect the switch to your ISP Hardware

Is there a reason for having two separate networks? How far apart are they? Can you establish a connection between the two networks?

As Scott stated above, it may be as simple as connecting the two switches together unless they are more than 100 meters apart. You may have to purchase a crossover cable instead of the typical straight passthrough cable. Depending on what switches you have, the last port in the switch may be able to handle the standard cable. There would be a little button next it to change the port configuration at one end.

The first PC we have two network card or (use router)
The first network card of the pc1 you connect to Internet why the second one we connect to switch through straight cable.
And the other will connect to switch through straight cable. After you done this, write click my network place on first PC click property.
Right Click on your network card that receives service, click property. Click on advance and tick the box of sharing network .
Wait for system to save setting go the second PC and ping IP Address of you first computer or ISP IP Address