|thank u sir, i compared both of them, and yes both of them same in default gateway and in the subnet mask. |
Ok, that's going to be your problem. Basically, you have the exact same subnet on two separate subnets. If you try to connect two NIC's on PC, one to each, you end up with IP's in the same subnet and you'll only ever connect to one network, if you even get to connect to one.
I would suggest you change the LAN IP addressing scheme of one network or the other to a completely different subnet. Then you shouldn't have any trouble connecting to both at the same time with different NIC's on one PC.
Since you didn't post the default gateway IP's as I asked, I'll give you a rough idea.
The typical default subnet on most SOHO Router's that I've worked with is either: 192.168.0.0/24, or 192.168.1.0/24
If for example, both of yours are 192.168.0.0/24, change the LAN side of the other router to 192.168.1.0/24
Now, with both NIC's on your PC set to DHCP, each will get an IP address that isn't the same subnet and you'll be able to communicate with both networks.