Why can't I connect to any LAN's?

It won't work on my Windows 8 laptop. I'm currently at my friends house and there's a total of 4 of us. We're all on the same network and I can't connect yet the other 3 can. I already tried disabling my firewall and nothing. We're trying it on Garry's Mod and Minecraft.

Any help would be greatly appreciated.

Your router might be set to a low number of people able to access the Wi-Fi. Look in the router settings under "WifFi" and see if you can change the setting to include more connections.