router won't refresh/renew WAN IP address

[lilmac0822]

I have a cable modem from time warner which i had connected to my wr850g motorola wireless router. recenty i attempted to connect a fx polycom unit to my system for work purposes. in attempting to changes various setting on the unit the system must restart which possible knocked out some configs in either my router or cable modem. Here's the issue:
1. When I connect from cable modem via ethernet jack into my laptop, i get an IP address and can access the internet
2. When I go from cable modem to wireless router to laptop, i get the private ip address but can not access the interent. I then checked the settings on the router and notice there was no IP address under the WAN.

Any ideas as to why my wireless router will not retreive an ip address from the cable modem? I have reset the router back to factory settings and have refreshed the cable modem, several times with no success.