Is it possible to create a VPN between Windows 2000 pro machines?

Hi, in my working area I have 7 computers running win2kpro (all connected to internet), I want to create a vpn between them so that the backup software can backup on the server at head office (Windows 2003 server) . Can this be done without having to install any software application or not? If any software is needed please advise me
many thanks

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).