Home networking issues

I've got a home network that has been set up for some time. 1 computer directly connected to router, 1 wireless. No issues. I've since tried adding a laptop to the network, and have been running into some problems. Some info:

- All 3 systems are running windows XP. The direct connect desktop is running XP pro, the other two XP home.

- The laptop has connectivity. It is in the proper workgroup. It can ping both desktops. However, when I go to 'view workgroup computers', nothing comes up, except this error message:
"<Workgroup> is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions.

The list of servers for this workgroup is currently not available"

- The desktops are able to see both the other computers (including the laptop) in the workgroup. However, I cannot ping the laptop from either desktop.

Basically, I'm trying to enable printer sharing and file sharing on the laptop, and can't do it due to this. Any suggestions? Thanks in advance.

 

Fire wall??

 

This connection problem could be many things. I would check what kind of security you've enabled. Do you have the MAC filtering enabled? Check this out.