<<< when you try and access the PC from the laptop, access is denied is displayed >>>
1) Have you set at least one folder in the PC as "shared" by right clicking and selecting the Sharing & Security option?
2) Have you configured any third-party firewall software to allow access to the networked computers?
I don't actually understand how you have them connected - it sounds as though you have them "double" networked, once for internet access (although there appears not to be a router) and again for file sharing ????