When you right-click the Start button to open Windows Explorer, the default selection is a deeply buried user directory under C:\Documents and Settings. My organization is networked to a central file server that stores all our files. We wanted users to default to the server rather than their local computers when they used Windows Explorer.
So, we edited the HKEY_CLASSES_ROOT\Folder\shell\explore\ddeexec registry subkey. If you change this subkey's default value to [ExploreFolder("yourNetworkDrive", yourNetworkDrive, %S)], you force Windows Explorer to start at the drive you specify. Replace yourNetworkDrive with the drive you want. In my case, the drive is mapped as S: on all workstations, so the string on my system is: [ExploreFolder("S:\", S:\, %S)]. To present a single-pane Windows Explorer view, you can change ExploreFolder to ViewFolder.
I created a .reg file to automatically change the default Windows Explorer directory. Listing 1 shows this file. You need to change the two S: entries in the file to match your network's mapping (leave the %S entry as is).