My laptop is showing it is connected to the router but no internet works. Mac / IP filtering is off. I tried re-configuring the router, resetting my pc, uninstalling drivers and again installing but that doesnt help. Connecting via lan with the router also denies internet from working. My laptop works fine while connecting to other networks. Internet works though when less devices are connected in the network. As soon as other devices are connected my internet stops working. What could be the problem and how can I fix it?
Sounds like either the settings in the modem/router are set to only allow a certain number of devices, or your ISP has put a limitation on how many devices can be connected at a time.
You can check the modem/router settings via the computer (when it is connecting) and see if there are any settings change to limit access.
If there aren't, then I would contact your ISP and ask them about it. If the first person says no or they don't know, talk to someone else. It wouldn't be the first time I have heard of this happening.