Wireless Network Problem

I'm posting this for a friend, so the info I have is limited so I may have to put more details on this later, but I'm going to see if anyone can help me with the limited info I have. Here is the deal

I have a friend that has a desktop that has a wireless router plugged into the ethernet port. He has a cable modem going into the uplink port on the router. The desktop can get on the internet with no problems. He also has a printer setup wirelessly that he can communicate with also with no problems. Here is where he starts to have problems. He has a laptop that that cannot communicate with the desktop and printer. The only thing it can do it communicate wirelessly to the router only.

He's already made sure the firewall is disable and assigned all network settings statically to make sure all of that is correct. Also he's using XP SP2 on both systems. What could be going wrong that the laptop can ping the router, but cannot communicate with anything else wirelessly?

Cable modem should be plugged into the WAN or Internet port not the uplink port.
Take modem off power and router off power plug modem into WAN (Internet)port. Wait 30 seconds plug cable modem into power wait for status light to go solid then plug in router to power restart all computers and try the Internet.This should allow access to Internet.To share the resources they can follow the steps listed at this site.
http://www.onecomputerguy.com/networking/xp_network.htm

Or This site.

http://www.practicallynetworked.com/...g/xp/addxp.htm