I found a manual via the WNR model number. I have the pdf for NETGEAR Wireless-N300 Router WNR2000v2 User Manual. There is a v3 but hopefully v2 will do.
Forgetting what the modem address is, the instructions below are for a router address 192.168.1.1 which I believe is the default. Once the address has been changed you can use that to log in to the router
Get one PC going first. Connect to router with Ethernet. Assumed WAN port of router connected to the modem. The instructions are identical to the Russb thread I mentioned, modified.
1. Open a new window or tab in your browser
2. In the address bar of your browser (where the http address of the site you are connected to appears), type "http://www.routerlogin.net", no quotes
3. A login screen will appear. Enter the Username and Password that you have set in the Wizard and hit OK.
4. Bypass any firmware update screens by clicking Cancel or Back.
5. Change the router address to the default - see instructions 17-22
6. Get to the Basic Settings page. I assume no login to the ISP is required. If one is required, checking that option will bring up the screen to enter the information.
7. In the IP address, check "Get automatically from ISP"
8. In the DNS server, check "Get automatically from ISP"
9. Router MAC address leave at default
10. You have to save the settings. Click Apply.
Leave browser:
11. Go to the LAN connection of the PC. Steps may vary with OS.
12. Select Properties of the connection.
13. Select Internet Protocol TCP/IP, click Properties. Check IP and DNS to obtain addresses automatically. Do not enter any addresses or submasks
14. Back out of the settings (Close) until back at desktop or whatever
15. Open a new window or tab in your browser and try accessing the Internet.
16. If that is successful repeat steps 11-15 with the other PC.
This is the first stage to connecting. The wireless comes next if that is how you intend to connect both PCs. Then there is setting up the home network between PCs. We'll look at those once the basic router is set up.
To check your router IP address:
17. Login to router, type "http://www.routerlogin.net", no quotes in your browser (or 192.168.1.1 once set), Advanced, LAN Setup
18. IP address 192.168.1.1
19. IP subnet mask 255.255.255.0
20. Check Router as DHCP server
21. Starting address 192.168.1.2, ending address 192.168.1.254
22. Apply