The approach of checking gateway address.

1. Get the network information in PC.

1) In Windows7 OS, right click the network icon on the right-bottom of the desktoip.

2) left click the internet item of local network.

3) click the detail information.

4) There is the default gateway address. It is also the router IP address.

2. Use Cmd command windown of Win7 OS.

1) Use hot-key "win+R" to open cmd window.

2) Type in IPCONFIG command.

3) It will list a lot information of the network, including the gateway address.

Note: Above two approaches is suitable for most router. If still could not get the gateway address, please check the connection of PC to router. There are below reasons in case of no gateway address information.
1) The pc connection is ok to internet. But it is not through the router.

2) The ethernet connection between PC and router is not correct or not stable. Check the netcard.

3) The ethernet cable problem. Use the new ethernet cable.

4) The LAN port problem of the router. Change another LAN port.

5) The router problem. Change another router.