enabling file and printer sharing from B to A

[mb123]

Hello
I have two computers, desktop(A) and a laptop(B), networked through a wireless router. Operating systems win XP.

The WAN part works ok and they can both access the internet.

However, I find that file and printer sharing is only available in one direction and I can only see the laptops shared files in my desktops network places.
( even tho I can ping A -> B and B -> A )

Heres what i did to configure the network:

1. Run the network set up wizards and set up an 'office' workgroup
on each node.

2. disabled windows firewall and antivirus software

3. enabled simple file sharing on A ( win XP pro)

4. checked that all the connection protocols on the network adapters and installed TCP/IP , client for microsoft networks, file and printer sharing

Ive may also have tried setting up corresponding user accounts, but this didnt make much difference.

The link to www.practicallynetworked.com talks about manually configuring ip addresses before installing a router etc, and well i dont know if thats applicable.

I was wondering if someone can tell, what else i might need to check in order to get connected.

Are there some services that must be enabled on my desktop before file and printer sharing is possible? what are they?

thanks in advance

mb123