Cut the wireless connection to the main router, keep the extra router (router2) power down, connect the Ethernet cable from the computer to the router2, if this router have a WAN port don't connect to that one use one of the normal ports. Power on the router2 and wait to see if the computer gets an IP address, from the Windows Command Prompt use the ipconfig command to see if the computer got an IP address in the form 192.168.2.X (based on the information you provide)
If you changed the router configuration and disabled the DHCP server on the router2 already the computer will not get and IP and you have to configure a fixed IP address on the computer to something like 192.168.2.10 for example.
Is important to know the IP address of the main router and the DHCP range that is in set on that router because you should set the IP address on router2 to some IP on the same network (192.168.2) but with an IP address outside of the DHCP range.
Example: the main router with ip address 192.168.2.1 with DHCP set with the range 192.168.2.2-192.168.2.100
the router2 could have any IP address selected from 192.168.2.101 to .254 to avoid conflicts.
After changing the IP of the router2 and disable the DHCP server, connect router2 to the main router and change the computer configuration to use DHCP instead of a fixed IP.
Edited by SleepyDude, 22 July 2017 - 06:43 AM.