Maybe you are using windows, and maybe you are not aware why you should try something else. If this is the case you should really inform about the dangers it represents for you, your family and future generations, there is good information here; Windows Vista, Windows 7 and Windows 8.

Take time to read more about FSF and difference between proprietary, open-source and libre software. If you are not computer savy you can slowly get your self comfortable with libre solutions by installing them on your windows machine, maybe the most famous applications;

LibreOffice is a office suite solution.
Image Editing
Gimp is an advanced image edition tool.
Firefox is a browser with huge plugins community.

Once you feel comfortable using tools with higher intellectual and moral grounds, you can start thinking about testing an alternative to Operating System without messing with your current installation. This can be achieved by using Qemu.

Qemu on Windows

Qemu is a full computer system emulator that can be used to create several virtual machines on a single computer. Download Qemu 64 or Qemu 32 for Windows. Read windows documentation and visit Qemu official page.

Gnu/Linux distributions

There is so many alternatives that the best one really depends on your personal taste, this list is based on package system;

Distribution that replaces Debian without systemd, the project provide ready to use Qemu images, download them. Read more information about Devuan installers.
Derived from Arch plus stability and security from Debian, Hyperbola provides packages from it that meet the GNU Free System Distribution Guidelines (GNU FSDG) and replacements for the packages that don't meet this requirement. Packages are provided for the i686 and x86_64 architectures.
Distribution used by this project, CRUX is a lightweight Linux distribution for the x86-64 architecture targeted at experienced Linux users. The primary focus of this distribution is keep it simple, which is reflected in a straightforward tar.gz-based package system, BSD-style initscripts, and a relatively small collection of trimmed packages.

BSD distributions

MINIX 3 is a free, open-source, operating system designed to be highly reliable, flexible, and secure. It is based on a tiny microkernel running in kernel mode with the rest of the operating system running as a number of isolated, protected, processes in user mode. It runs on x86 and ARM CPUs, is compatible with NetBSD, and runs thousands of NetBSD packages.
The OpenBSD project produces a FREE, multi-platform 4.4 BSD-based UNIX-like operating system. Efforts emphasize portability, standardization, correctness, proactive security and integrated cryptography.
NetBSD is a free, fast, secure, and highly portable Unix-like Open Source operating system. It is available for a wide range of platforms, from large-scale servers and powerful desktop systems to handheld and embedded devices.
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.

First Login

If is your first time using a GNU/Linux Crux someone must had installed and configured it for you. When you turn on your computer you see a menu, this menu is the grub bootloader.