You don't need a CD - there is a web interface. First, download the user manual here
I suspect your problem is the Linksys/Belkin combination. Linksys by default uses a subnet of 192.168.1.xxx while Belkin uses 192.168.2.xxx. With a subnet mask of 255.255.255.0 (the default for both), no communication would be possible between these two subnets. The "255" in each of those first three octets means they must match exactly.
Either move the Linksys to 192.168.2.xxx or the Belkin to 192.168.1.xxx (and keep the same subnet mask) OR you can change the subnet mask to a broader one (255.255.254.0) that allows the two different subnets to talk to each other. This subnet mask would have to be applied to both devices.
According to the manual, the default address of the Belkin is 192.168.2.254, which leads to your next problem - your PC probably can't connect to the Belkin device. Assuming your PC is configured for the Linksys subnet, the easiest way to communicate with the Belkin is to use a network cable directly
linking your PC to the Belkin (may need to be a crossover cable) and manually set your PC's IP address to one in the same subnet as the Belkin, like for example 192.168.2.200 with a subnet mask of 255.255.255.0. Then you can open your web browser and point it to the Belkin default address, as outlined in the manual, and make whatever changes are required.