Gateway problems

[SystemDown]

So my friend has 2 PCs and he has built another one, after connecting the other pc it doesn't have any internet even though we installed and reinstalled all drivers, after restarting all systems we the newly built pc has internet and the main pc doesn't have any, after a few more tries we concluded that the last pc to boot up wont have any internet, so i was wondering what to do? is it a gateway problem or is it with the router? please help us out

 

[RealBeast]

You may need to alter the settings in the router to allow more connections. Open the router configuration pages, and in the section on DHCP address assignment check to see that the allowable address range is more than three devices. Also, insure that each machine is automatically obtaining an IP address from the gateway.

If he is using static addresses, insure that each machine has a different address; also best to have each machine on the same workgroup so that they can communicate with one another.