home networking not working

I am trying  to set up my network and I can access all of my files from my PC on my Notebook but I cannot access my Notebook files on my PC.  Both systems are running a version of XP, I have shut off both firewalls (PC runs Norton and the Notebook runs Trend).  Every time on the PC I get "Laptop is not accessible.  You might not have permission to use this network resourc.  Contact administrator of the server to find out if you have access."  I have been working on this for some time any help would be appreciated.  Thank you.