Rabs

I have a HP Pavilion desktop and HP laptop both running Vista and I have
recently installed a Belkin wireless router. In it's simplest form it is
working well, allowing us to access emails and the internet. It won't
however allow us to recognise the other computer - ie they are operating in
isolation. Whichever computer is turned on first, gets the email so they
can't be seen by both computers. I also cannot see shared files.

Can you please advise how this might be possible to set up?

thanks