Ok, so you can log into the other computer on the network but you can't see the drives or folders?
Check the share properties of the drive by right clicking over the drive in My computer or Windows Explorer. In the share name field you need to name the drive as something other than C$ or D$ which are not viewable on the network. At the bottom you will see "New share" and "Remove share" buttons. Use these to create drive names that you can view through the network. For example, all my drives are named after transformers. My MP3 box harddrive is named accordingly. You can also name drives for removable media, and pull data from loaded drives...it's cool installing a game from one computer onto another through the network...works pretty well too!