Even though Microsoft Windows is completely proprietary software - the philosophical opposite of open source software - it is very widely used all over the world. Most of our customers use it in addition to Linux and other open source software. Luckily for Microsoft Windows users, plenty of open source developers have chosen to focus some of their efforts on open source software specially built to run on the Microsoft Windows platform (MS Visa, XP, 2000, NT, 98, CE, etc.). Have a look at some of this jaw-droppingly-good open source software available (at no cost) to run on computers running Microsoft Windows:

• OpenOffice - full featured office suite - MS Office compatible drop-in replacement. Its native file format is the industry standard ODF format family. Killer feature: it lets you generate PDF documents on the fly without needing extra software!
• Gaim - replacement for MSN, Yahoo!, AOL, and other instant messengers.
• Mozilla Firefox - fast, efficient, safe, feature-rich web browser - drop in replacement for unsafe and non-standards compliant browsers like MS Internet Explorer 5-7.
• Evolution - a full-featured email(POP/IMAP)/calendaring/contacts client, allowing you to interact with many of Microsoft Exchange's proprietary protocols - a drop in replacement for Microsoft Outlook.
• Mozilla Thunderbird - fast, efficient, safe, feature-rich email (POP/IMAP) client - drop in replacement for MS Outlook Express - excellent anti-spam features.
• WinSCP - a very good Windows Explorer-like Secure FTP client. (We don't, by the way, encourage the use of non-secure FTP under any circumstances, as the protocol transfers your username and password to remote machines in a way that anyone can see them - not good practice!)
• The GIMP - excellent drawing, photo manipulation tool, very similar to Photoshop.
• Inkscape - a vector drawing programme similar to Freehand which stores drawings in Scalable Vector Graphics (SVG) format.
• 7-Zip - replacement for WinZIP - better compression, no annoying nag-ware popups.
• CDex - converts CDs to MP3/OGG/WAV files to play from your computer.
• Audacity - superb, easy to use multi-track sound recording system.

You can either download and install individual applications above, or get them all (and more - complete with a user-friendly installer) except for ClamAV by grabbing the OpenCD, a free download.

The real beauty of using this software on Microsoft Windows is the fact that most of it also runs the same way on open source platforms like Linux. If you like using, say, OpenOffice, the Gimp, Firefox, and Thunderbird on Windows, then you'll find you can use the identical software on Linux should you ever be ready to take the plunge and shift to a truly free (in the "freedom" sense of the word) solution.