Network setup as per picture below:
The DLink wireless router had DHCP and UPnP turned off so it was only acting as wireless access point/switch.
Everything was working fine up until last night, while I wasn't home my brother plugged a network device into the WAN of the DLink wireless router. The internet then stopped working and all devices attached to the Wireless switch showed the network error "Limited network Access"
So far I have done a factory reset on the Dlink and tried setting up as it was before by:
-Turning off DHCP
-Turning off UPnP
-Setting the IP of the DLink to 192.168.1.101 (After the reset the ip is 192.168.0.1). The DHCP range of the Vodafone router/modem is 192.168.1.2-192.168.1.100
However when i plug the vodafone router/modem back into the DLink and try to repair the network of one of the PC's attached to the DLink, it fails and shows a message that there is no connectivity in the network.
So i opened up the CMD and ran arp -a and it showed that 192.168.1.1 (which is the ip of the vodafone router) is invalid.
What is wrong with the switch? how do i get it to work again?
Note: The router are at opposite ends of the house (About 30m) and I had the DLink before I got the Vodafone Modem/Router so that's why I have this set-up