cannot access files over network

> Help,
>
> I have a desktop and laptop both running XP Home. A
> wireless router is connected to the desktop through it's
> NIC card. The laptop has a builtin wireless card. The
> laptop is NTFS and the Desktop is FAT32.
>
> I can surf the web with either computer, I can access the
> printers connected to the desktop with either computer
> and I can access shared laptop files from the desktop.
>
> What I can't do is access shared desktop files from the
> laptop. I tried the following with no help.
>
> 1. disabled Norton Internet Security on both computers.
> 2. Unchecked the XP firewall on both computers.
> 3. Made sure that any files I wanted to access are in
> shared folders.
>
> Both computers are workgroup name MSHOME and each has
> only one administrator. The error message I get each time
> is \\<computer name>\ (The correct computer name is seen)
> is not accessible. You might not have permission to use
> this network resource. contact the administrator etc. etc.
>
> Thanks,
> Jerryc
>