networking problem

Hello all:             Heres the layout of my system

3 computers- a dell deminsion e510/windows xp pro mce 2005

                     an hp desktop pavilion/windows xp home

                     an hp laptop pavilion/windows xp pro mce 2005

                     netgear wireless router mr 814v2

                     satelite internet with modem

modem connected to router/both desktops are running ethernet cables, laptop wireless, all get on internet fine.   problem is this, the 2 hp can communicate to each other, the dell can not at all

heres what they read when i go to my network places

dell/my network places/ i can see hp desktop & dell only, but when i click on hp it reads-

\\your-hp\shared docs is not accessible. you might not have permission to use this network.

but i can open up the dell one

 

desktop hp/my network places/ i can see all 3 computers on it& open both hpcomputers, but not the dell,  it reads the same as above

 

laptop hp/my network places/i can see all 3 computers on it & open both hps but not the dell

all computers have windows firewall on & so does the router, now i have tried to disable all firewall too still nothing, now im lost here so i would appreciate any help.

          thank you very mush          keith