vista laptop cannot access network shared folder of xp pro desktop

I am running Windows Vista on my Acer Laptop. I have also got a desktop computer which is running Windows XP that I have set up as a home network between the Vista operating system. I am able to access the all the shared folders on the Vista laptop when I am using the XP desktop, but if I am trying to access the desktop from the laptop then it comes up with a message that says "cannot access the computer //Username, check the spelling or your network connection". And when I am trying to view the network map then it wont let me to click on the XP computer at all? Can anyone tell me how do I access the XP computer? Thanks

You might need to create same username with the same password on both the computers. Or else try the below solution and see if that works:

1. First of all enable guest account that is not recommended for the security reason.
2. After that try to assign everyone full rights in the Security tab that is no secure too.
3. Now you have to create the identical username in all home network computers.
4. There is a more secure way by assigning users necessary rights to the shared folders based on their needs.
5. You will also need to make sure share permissions must match the folder security for access to a share.

Have you tried to run Windows XP's File and Printer Sharing wizard, so that it will let you to access Windows Vista as well? In any case, if you are also running Norton firewall or some other third party firewall then try to make sure that you have given permission to access the files and folders, or even disable it and check if you can access.