You can set the number of DHCP addresses available to be assigned in some (if not all ) routers. If you're using all of the addresses, then perhaps disconnecting from the switch frees up one of the DHCP addresses, thus re-enabling the Wi-Fi.
I have my DHCP server from the range of 192.168.0.150 - 192.168.0.199. There are only a maximum of 8 connections at one given time (wired and wireless) so I don't think its a DHCP issue because even when I reset the router and the only computer connected is the one that I am using to configure the router I am having this issue.
Even with all the connections the network (local) is available and it looks like the router is connected to the internet because on the main screen it gives an external IP from the modem. Just when you connect to the router it says there is no internet on your computer.
To Start Press Any Key'. Where's the ANY key?
If something's hard to do, then it's not worth doing
You know, boys, a nuclear reactor is a lot like a woman. You just have to read the manual and press the right buttons.