Two routers in series? Noob

I have a LinkSys 4 port/802.11b router and want to connect, by wire, 4 cpu's (all CPU's are running Win XP Home or XP MCE) and 2 Xboxes with ethernet ports. I also have an older Belkin 4 port wired router that I almost never used. Can I use the fifth port on the LinkSys router (Uplink) as a WAN input to the Belkin router? Instructions says, in doing that, it'll sacrifice the fourth port on the LinkSys router while the uplink port is in use. That's okay with me, if it works. So far, it only works intermittently.

Also, I'll need to be able to stream Video from two of the CPU's (all CPU's are running Win XP Home or XP MCE) to two of the Xboxes. Will all four components ((2 CPU's and 2 Xboxes) need to be on the same router?

I've already tried using the Uplink on the LinkSys, to the WAN on the Belkin and am getting a "LAN cable is unplugged" error message. And the Media Center CPU becomes disconnected from the Xbox without anyone touching anything. Wiggling wires seems to have no effect. I go the the Network connections and Disable, then Enable, the connection and it seems to work for seconds, then gives the "cable disconnected" error. Do I have a problem due to the serial use of the routers or do I need to open-up the ethernet outlets to make sure the connections are sound?

Thank you,
Fireball (Noob)