A long delay occurs when you try to open a network share by entering a path in the Run box on a Windows Vista-based or Windows Server 2008-based computer
On a Windows Vista-based or Windows Server 2008-based computer, you try to access a network share by typing the path of the share in the Run box. However, it may take more than 10 seconds for the network share to open in Windows Explorer.
For example, in the Run box, you type the universal naming convention (UNC) path of the share, such as \\ServerName\ShareName. When you do this, it takes the Windows Explorer more than 10 seconds to open the share.
This issue occurs if the firewall of the server on which the share resides blocks traffic on port 80.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB958970.