Windows by default creates hidden shares of hard drives, called administrative shares. Additionally, you can create your own hidden shares. Since these shared folders and drives don’t show up in My Network Places or Network, you need to know how to access them from other computers on the network.
To access a hidden share, bring up Internet Explorer or My Computer (or just Computer in Vista), enter the UNC path (\\computername\sharename$) of the share, and hit Enter. Alternatively, you can use the computer’s local IP address (such as 192.168.1.1) instead of the computer name. The trick is to include the dollar sign at the end of the share name. Then depending upon the permissions you specified for the hidden share and the Windows account you’re currently logged onto, you’ll either have to enter a username and password or be given access right away.