Laptop with wireless card failed to connect other desktop PCs

Hi:

I use a 4-port router which also has a wireless port. I have a few PC
connected to the 4 ports at the router. I also have a laptop with wireless
card connecting to the router's wireless port. The problem is that the
laptop can work with internet fine but cannot connect to any of my desktop
PCs.

Any help is appreciated.

Thanks
Polaris