Great question! So many companies just assume they need a server. This is not true. Windows 2003 Server can be used to
Authenticate Users (Active Directory)
Setup Exchange (Email)
Setup SQL Server (Database)
Use as a file server
Host a web site
Host a FTP site
Have a central repository for user profiles.
Now if you don’t need these functions or you outsource them you can have a serverless environment. If you only need a file server you can use older versions of windows server OR even older hardware. JUST BUY NEW DRIVES!