file sharing thru dlink router

[jrtmx8]

I have a Dlink wireless router that lets me share my dsl between a wireless computer and a computer plugged in the back of the router. How can I enable file/printer sharing between the two? I have win XP and have run the network setup wizard on both comps but it does nothing.

[jrtmx8]

Also, while talking to a Dlink tech support guy he told me to type in ipconfig in the cmd prompt, it said 'ipconfig' is not recognized as an internal or external command. It said the same for ping too.
...is this bad?