In the Vista PC, go into the "Network & sharing Center" and switch "On"...
- Network Discovery
- File Sharing
- Public Folder Sharing
- Printer Sharing (if applicable)
The "Public" folder should automatically be available over the network. Set any other folders that you want to be able to access as "shared" by right clicking and selecting the Share option. If you log in with the same Username/Password in both computers, you shouldn't need to add another User, otherwise add the Username with which you log into the Laptop with.
In the Laptop, when you go into "Network", you should see an icon for the Vista PC. Double clicking it should show the shared items that you can access.
See how you get on with that.