This is a little late, but better late than never.
Being geeky, and somewhat anti-Microsoft monopoly, I have a soft spot in my heart for open source operating systems and software. The definition of Open Source, according to http://www.opensource.org is: "...a development method for software that harnesses the power of distributed peer review and transparency of process. The promise of open source is better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in."
For those of you who prefer plain English, here is an explanation.
When you use Windows, you are using a set of programs that you only have minimal control over. The control is decided by Microsoft. "Tampering" with the programming is forbidden by the terms of service. Have you ever read one of those? Many of them look like a lawyer self-destructed leaving a convoluted pile of rules.
Enter open source. Open source, as we know it today, was the brainchild of Linus Torvalds, the originator of linux. Linux itself was designed to emulate Unix, which is generally considered the most stable operating system available. Unix is for larger machines, whereas linux is for smaller computers, like most of us have today.
There are many flavors of linux (known as distrobutions, or distros) available for free online and it is perfectly legal. The different versions may have small nuances different from one another or they may seem like totally different operating systems. Not only that, since the source code is editable you can change and tweak your operating system to do things your way. If you think your changes would be beneficial to a segment of linux users, you can submit your source code for consideration for inclusion in one or more versions of linux. This allows users to fix or augment their favorite distro of linux to suit them without any repercussions.
Linux is not the only software available in an open source version. Open Office is the open source community's answer to Microsoft Office. The following list shows the Open Office programs and their counterparts in Microsoft Office
Open Office also contains a module called Math that create and edits scientific formulas and equations.
There are many other open source programs out there. All you have to do is look.