If the router is assigning the ip addresses then all machines need to be on the same network to be able to see each other. If the router is told that its address is 192.168.8.1 then all machines need to be on the 192.168.8.xxx range. Any other routers connecting to that router need to be on their own range 192.168.xxx.xxx and the gateway of those other routers point to 192.168.8.1. All of which need to be on the SAME subnet mask 255.xxx.xxx.xxx
The PC being on 192.168.1.xxx will stop it from being able to interact on that 192.168.8.xxx network. Change the devices connected to the router to DHCP or put them static on the same network and the network will jump into life.
After thought… Change the gateway address on the PC to 192.168.8.1 and see if that does anything while the rest remains on the 192.168.1.xxx settings.