Cant get computer to see network

[artsim47]

I have 4 Dells 2 desktops and 2 laptops. Both dekstops are XP both Laptops are Vista. All are online and can connect to the internet. One desktop and 2 Laptops are wireless. The problem is that the Main desktop the the combination router/modem is connected to will not see the other computers. I also have 4 printers all shared with the main computer. I used to be able to print from any machine untill recently. I can ping the others. After looking through the forums here I dloaded netscan and after running it the main computer sees the others however I cannot add them in my network connections. From the computer I am typing now can see the main when I click on a shared drive it says I dont have permission or not available. I know this is a long post but I am at my wits end. Also I have wireless Laser printer that that the 3 others can print to.
I dont know what I am doing wrong. Please help. I can see ALL printers and I know they are shared but cannot print to them.Wireless from here i can see the laptops and the entire network. They all have the same name MSHOME.
Thank you
Art

[PeterB]

Hi artsim47
You are probably running firewalls on your different machines. try to disable them, and see if this helps. then it is your firewall that is your problem. about network share. you can have a network share that shows up on one pc, and then you try to connect it says "..dont have permission or not available..". then you should check up on port 137+138+139+445. and see if they have been blocked. on xp port 445 should replace port 137+138+139.
This may be helping, check this: http://www.petri.co.il/whats_port_445_in_w2k_xp_2003.htm