i have a desktop that has windows XP (OS) and a laptop that has windows vista as OS. they both are connected to a adsl router/modem that helps to connect both to the internet. now i want to share some files between these two computers. how do i access the other pc's files ( i know i have to make them shared by changing their properties) but the problem here is i am not being able to access or view the other pc's shared content. however they are in the network. the ping command works using each other IP addresses. some body help me to view the shared contents and to share the files.

does it have to do anything with one having XP and the other having vista ?

Assuming you have a software based firewall installed on each computer, you must add the other computer's IP into each FW's "Trusted Zone".

i dont have any other firewalls intalled it's just the firewall windows has. n it has no provision for adding ip address to it's exception list. it says only programs and port number to be added.
but i think still u didn't got the idea of my problem .
i don't know the method to acces other computer...i mean whether to enter the ip address in the windows explorer address bar or enter in the RUN window. i tried both but to no avail.

it has no provision for adding ip address to it's exception list

You should be able to change the scope of File and Print sharing, then add the IP for the other machine.

Once your firewalls are setup properly, you connect to the other computer by clicking Network Neighborhood, where you should see your networked computers.

sorry for replying late..
when i view the list of computers connected to the same network from my desktop(running windows xp) it shows my laptop (as Dell-PC) but when i view the network from my laptop ( running vista) it only shows the adsl router and itself and does not show the desktop computer.

Did you add each computer's IP to the other's Firewall?

Change the Scope of an Exception: Windows Firewall (WF)

in the vista when i try to change the scope it also requires to enter the name and the port..what name and port number am i supposed to enter at that ?

According to that link above, you need to select Custom list, then enter the specific IP of the other computers. If you do not know what the IPs are, you can look in the "Client List" in your router's configuration menu, or you can open a command prompt on each machine, and enter: ipconfig (enter ipconfig /? for a list of ipconfig options - ipconfig /all being one of the most informative).

If you have several computers (maybe a networked printer or storage device too) on your network, using a "range" of IP addresses is easier, as you only have to do it once.

i guess u didn't got the problem right..
i was saying in vista it didn't let me enter the ip address only, without entering the name and the port number in the custom list . i have no idea what to enter in those two fields.

and i know the ip address of both the computers.