ActiveXperts Network Monitor 2015 proactively manages network servers, devices, databases and more.

Microsoft Resource Kits - Windows 2003 Resource Kit

Oh.exe  (Windows 2003 Resource Kit)

The Window Server 2003 Resource Kit is a set of tools that system administrators and engineers use to manage or support a Windows Server 2003 system. Use it to streamline management tasks such as troubleshooting operating system issues, managing Active Directory, configuring networking and security features, and automating application deployment.
Oh.exe - Open Handles
This command-line tool shows the handles of all open windows. You can also constrain OH to only show information relating to a specific process, object type, or object name. This feature is useful for finding which process has a file open when a sharing violation occurs. To function properly, OH must enable a kernel option which maintains a linked list of all objects by object type. If not set, OH enables this option and notifies you that you must reboot before OH will function. After rebooting, OH can display information.