How do I fix my router so the connection wont fail everytime I have 2 computers connected?

if you have a netgear router, type in 192.168.1.1 in your web browsers url field

you will have to give the devices diferrent ip addresses 192.168.1.1

192.168.1.2

192.168.0.1

192.168.1.3

and the same network subnet 255.255.0.0

Back sure that you have a router, not an access point. Additionally, make sure you have the cable modem connected to the WAN/Internet port of the router, not a Lan/internal port. Make sure both DHCP and NAT are turned on on the router.

The problem is that if you don't have DHCP and NAT turned on or if this is just an access point, that it will cause your router to act as a switch or hub, and therefore trying to pull outside IP addresses from your cable company via the cable modem. Since many cable companies only allow one IP to residential users unless people pay additional fees, this is likely why a second device is causing you problems. NAT fixes the problem by making the router act as a "gateway" between the one IP address the cable company gives and your private network internally.

It might be your DHCP clients table doesn't have enough open slots. If you go to you router's setup, find a page that mentions DHCP clients. On routers I've seen, it is usually set at 100 by default. Make sure it is as many as the devices you are trying to connect(or more, 100 is fine). Also make sure that DHCP is even on, if you have that option, then reset both the modem and router and try again. Leave the modem off for 5-10 minutes before powering it up. The router doesn't need such time, just make sure it is on before the modem.

Reset the router back to factory defaults. Make sure to press and hold the reset button for at least 10-15 seconds. Also power off your cable modem, remove the cable from the modem, wait a few seconds and try your connections again. Also try another cable and make sure you are connecting the cable to the right port. Wan should go to your Cable modem. Your computer should be plugged into one of the numbered ports.. The key is to reset everything and start from scratch...Good luck

Make sure you're not using the same IP address for both devices. Use DHCP for both, or statically set them to different ones.