Hi ,
As initially linux kernels did not support sis 190 driver I had to get a realtek8139
lan card . But now in ubuntu dapper kernel 2.6.15 I find that my both lan cards get detected .
But the problem is whenever I use SIS 190 lan card I am able to do "ssh" to other computers and "ping" also works fine . But when I try to open anything in browser . It just does not open . Can anybody tell me what can be the problem ??

Probably you do not have any nameserver lines in "/etc/resolv.conf". I suggest doing a ping test of a web site. If the ping comes back as an error after some moment has past, you will need to gather DNS IP addresses. You need at least two DNS IP addresses. If you do not know the syntax of resolv.conf, type 'man resolv.conf'. After you got the DNS IP addresses, you will need to setup gateway address that is handling your WAN connection or internet. If you have DHCP utilities installed and you have a DHCP server on your network, setting the DNS IP addresses, gateway address, and IP address is automatic upon boot up or re-running the network settings.

I suggest use one of the NICs that you have unless you are setting it up as a router.

Thanks for your reply but I have set dns address in resolv.conf and anyway when I try directly ip address in browser of any site it still does not get opened .