Basics....
Since you've recently (I'm assuming) revamped the IP addressing scheme for the network from Class C to Class A, then
Use the ping command from a command prompt to determine that all network nodes are reachable from the windows 7 machine.
One question, were the Win7 machine(s) on the network and working properly when you had the Alink router setup? Just want some clarification.
Also, check within the Belkin web interface (all routers are a little different) for something called UPnP (Universal Plug and Play) make sure that it's enabled.
Check the Belkin website and see if there is a firmware update for that particular router.
Also, leaving the IP camera(s) out of the equation...define your actual problem
Is it, as you mentioned before, Win7 cannot (see?) (or access?) your NAS(s) device(s)??