XP / Vista networking

I have recently installed a fresh version of XP Pro on my PC. Since then I
have problems with my network with a Vista Home Premium laptop. Previously I
have had no problem with networking both machines which are connected by
ethernet cable
I can access the vista files and transfer to and from the PC but if I try to
access the PC from the laptop I get the error message;
Windows cannot access \\PC1
“Check the spelling of the name. Otherwise there might be a problem with
your network. To try to identify and resolve network problems, click Diagnose�

Clicking diagnose brings up the message:
“Windows did not find any problems with this computers network connection.�

I can access the internet from the laptop using the PC’s connection, and the
PC appears on the network map and in windows explorer on the laptop.

I have tried removing the Firewall and antivirus on both machines, and
various registry alterations as suggest for this error on numerous other
forum without success.

Fortunately I can manage with just the connection from the PC but it would
be nice to have things working both ways. Does anyone have a solution that
works?