internet connection sahring

Hello
please help me regarding this
I have 2 nic .1 is directly connected to router .that is dsl router...and and have also a vpn connection. And the second nic is connected to the switch .both router and switch are conected to lan ports. Now I shared my vpn connection with second nic . That is connected to switch. Now when I conect and pc to switch there is no internet access in that pc. But status shows in double nic cmputer shows that bytes are sending and reciecving.
then why internet is not working on that computer that is connected to switch