Can't ping other computer on home LAN

I want to fileshare between the desktop here and the laptop across the hall (both running XP Home). The two pcs and a cable modem all connect to an ethernet hub. Both can connect to the internet just fine, but neither lists the other's shared folders in My Network Places.
I went through the Network Setup Wizard on both computers, turned on sharing for the appropriate folders, and XP's ICF is set to allow file sharing.

Both computers can ping themselves. The laptop can't ping the desktop by ip (timed out) or by name (host not found). The desktop can ping the laptop by ip but not by name (host not found).

What should I do now?

 

This is a link to a good page describing how to set up a simple network. Start by following through the procedure described there (obviously you are using a hub and straight-through cables rather than crossover cables, but the configuration of the computers is the same).

You can also use this tool to check you've selected compatible IP addresses