Switched to cable(arris modem) can't set up network

Since I switched to a bundled cable pkg. I've been unable to set up my network. My netgear router can't seem to work with the arris modem, and my belkin adapter can't pick up the signal. It's driving me nuts as I've tried everything. Cable says it's the router, they say it's the modem, they say it's the adapter etc. Cable said their system is too fast for my router. Help me!