XP does not browse network

I installed a new PC with Xp on it. Most of users, 8 PC’s in all, have Win98. It is a peer to peer network.
At first I was able to see all the clients but now they do not show in MY Network Places.
THey can see me but I cannot see them.
I installed netbuie but and uninstalled and reinstalled it but still cannot see the other PC’s.
Any ideas.