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

Microsoft Resource Kits - Windows 2003 Resource Kit

Diskuse.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.
DiskUse is a command-line tool that scans directories on a hard disk and reports on space used by each user. This tool can scan a single directory, a directory tree, or an entire drive and can extract information on one user or all users. Reports can be displayed on-screen or output to a file, in table or text format. DiskUse can also list all the files owned by a user or users, filtered in a variety of ways