home network help required please

[Mr Mag00]

I have an addon router to which are attached wired on a LAN 2 pc and from time to a wireless lappy.
Now 1 pc and lappy can see each other, but not one of the desktops.
The laptop was the last computer to be added to the network and it has no problems.
What are the setting changes i need to make to the pc to see the other computers? this pc is the original pc in the house and is running xp, they are all running xp.

ta

 

[ns400r]

Start by checking the workgroup and also the state of the firewall.

 

[Mr Mag00]

workgroups are all the same. the firewall as far as i know is ok, but i will check. *edit* the file and printer shRING re turned on, ive turned off firewall and it would not find the other computers

is there any way to reset it all on the original pc?