Windows 7 and NAS connection Issue

Hi,
I recently bought a new HP Pavilion dv6 laptop with Windows 7 Home Premium and I have got a Western Digital My Book World 1TB hard drive. I can see the contents of the hard drive from my other laptop with has Windows XP, however I cannot access the contents from Windows 7. I can see the folders, however When I try to access a folder, I receive the following error message

"\\MYBOOKWORLD\Public\"foldername" is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions.

The specified network name is no longer available."

Are there any Windows registry setting which need to be changed in order to allow access? I have tried disabling the firewall and anti-virus, but still does not allow access.

Is anyone able to help?

Thanks in advance.

This sounds like a Permissions problem. I'm not an expert in this stuff but since you haven't gotten any answers yet I will offer an idea I think might work:

Attach your NAS's HD directly to the W7 computer and then open Windows Explorer and right-click on the root directory for that drive. Go to the Security tab. Under "Group or User Name" click EDIT and in the new window click ADD. Add group Everyone and check off to allow the permissions needed (at a minimum you should check Read & execute, List folder contents, and Read ... but you will need others if you also wish to write TO the drive). Now put the HD back on your router. Post back the results.

Note: if it doesn't work you can simply repeat the process and delete group Everyone