I've seen this with some routers. I don't see the router, router version and the firmware installed on the router.
It could confuse folk new to this issue why I ask but it's one of the causes.
So I got this new Dell XPS 14z (Windows 7) a few months ago. I already had two laptops at home, and the internet always worked fine with them. I have a Toshiba Satellite (Windows 7) that is connected through the ethernet, and a Dell Latitude E6400 (Windows 7) that is connected through the wireless.
The problem is, when I connect my XPS at the same time as my other Dell, the internet only works for about 30mins. max and then crashes. I am using a Cisco Linksys router. When I only have one of the two laptops connected at a time, the internet will work for hours.
I have already tried renewing all of the computers IP addresses, and none of those are in conflict. I made sure that all of the computers were set to have IP addresses assigned to them automatically, no static addresses. I have reset the router, I have disabled all of the other connections on my computers, I really don't know what else to do. These things have helped to improve the amount of time the internet works, it used to be about 10mins. max, now it's more like 30mins, but that's not good enough. Now the internet comes back a bit quicker than before as well, instead of taking 3-4mins, it takes about 1-2mins instead.
Also something really weird about the wireless is that on the XPS it says "connected" but also "no internet access" so the internet isn't working on my XPS, even when there is internet according to the router, and on the Toshiba. If I disconnect and reconnect, then the internet comes back to my computer again...
I would really appreciate if somebody could tell me what is going on. Thank you in advance for helping out.