There are many reasons why people use Linux but the top four reasons are speed, security, stability, and cost.  Now, let's look at these top four reasons.

Speed and Security

 Most Linux operating systems take slightly longer to boot into the desktop than Windows XP on the same computer. (It doesn't appear to be the case with Windows Vista, but I won't even go there.) Once the desktop is loaded, it's a different story. Instead of waiting for startup programs such as MacAfee or Norton Antivirus to finish loading and/or scanning your drives, you can immediately launch your browser and go straight to the Internet without the usual wait, or start working on your files sooner.

 Antivirus and anti-spyware programs are not even needed or used on a Linux operating system. The only exception could be if your Linux computer is on a network with Windows computers and you need to scan incoming e-mail. One reason why there is no need to worry about viruses or spyware is due to the fact that Linux is a user based system. Any changes made to the system files have to be done by someone logged in as the root user. A couple words of caution are in order here. Never, ever log into the desktop as the root user. It is just asking for problems. Temporarily logging in as root to work on your system through a terminal is fine Also, as with any other operating system, you should also be using a firewall.

Another reason why Linux is more secure than some other operating systems is due to the fact that there are very few malware programs such as Trojans, worms, viruses and spyware written for Linux. Windows, with Internet Explorer takes up at least 90 percent of the desktop market and it is the most popular with online criminals who write these programs.

Stability

 Using Linux, you will never have to worry about the infamous blue screen that signals an end to your computer session and any unsaved work, or the DLL (Dynamic Link Library) files that have seemed to disappear, along with the program that you have just uninstalled. Linux computers have been known to run for over a year, without even needing to be shut down or rebooted for any reason.

Cost

 Cost is certainly a major consideration for anyone facing an upgrade or replacement of their computer. The retail price of the upgrade version of Vista Home Basic is $99.95 and the full version is $199.00. In order for Vista to run right you may need to upgrade your computers hardware. A new DirectX 9 class video card can cost $68.00 to $150.00. Adding one gig of memory is about $100.00.  The hard drive needs to be at least 40 gigs with 15 gigs of free space. There goes another $100.00, if not. A DVD rom drive is required as well. Just upgrading the operating system to a minimal version of Vista and the hardware to run it can cost anywhere from 168.00 to more than $450.00. This does not even include a word processing and spreadsheet program for at least another $124.00.

You can install a free copy of Linux that is loaded with lots of useful applications such as Open Office.org which is the equivalent of Microsoft Office. Many Linux distributions do not have anywhere near the hardware requirements of Windows Vista. If you can't live without some Windows based applications such as Quicken, there is an easy to install program that will let you run them on a Linux system called Crossover , which is available from Codeweavers.com. The cost of this program is 39.95 which is a one time fee.

To sum it all up, if you are looking to upgrade from your present system, you have a couple of choices. You can buy a new computer to replace one that is still perfectly good or do an upgrade to Windows Vista. Either way can be expensive. Your other choice is to install a distribution of Linux. Depending on your requirements, your total cost could be from $0.00 to about $105.00 for a far more stable and secure system. The $105.00 would be for someone who needs to run Windows based programs and is still has a dial-up connection. A serial (hardware) modem is about $65.00.