File sharing issue

I have 7 computers in a small network. And I am a newbie. We are not running a server as the domain controler, but as a backup system of data. I have these operaiting systems on the ” network”

WinXP, WinXP home and Win ME. Basic cable router hub combo situation.

I cannot get the file we need to share to be seen consistently on the network.
I want to make sure I’m doing things right.

I have made folders in the “shared folder ” area available. I click on network places, I can see all the computers. I have turned off the ” windows firewall” but still its a hit and miss with seeing those files.
Forgive my ignorance, but I need to fix this. Can I have the best solution from you wonderful folks??