I suggest that you give Linux Ubuntu a try just like I did about a week ago.I currently have Ubuntu running as my main OS on my desktop PC , and all I can tell you that as long as you do some reading to get familiar with this distro you will love it in my opinion. Or any other distro for that matter, but Ubuntu is really designed with the intent to help newbies get it and use it. This is a perfect Linux flavor for a newbie. I dipped into Ubuntu last week. All this hype and interest in Linux got me very interested in Ubuntu. But I was at the same starting point as you are now. Ubuntu is basically another flavor or version of Linux disto. I suggest that you take a look at the following resources. As to where can you get a a copy of a chosen distro. That info can be found on each distro's site.
Take this test to help you decide.
http://www.zegeniestudios.net/ldc/
Info on all Linux distros with links to sites and downloads
http://distrowatch.com/
I like this site because if you have a problem the response is great.
http://www.linuxquestions.org/reviews/index.php/cat/2
Selecting the right distro for a newbie
http://linux.about.com/od/popular_distros/
Look for a distro with a Live CD option as this will let you try the distro by running it in Live Mode before installing it. The Live CD will not disturb your Windows OS environment.
Also, checkout my post over at Leo Laporte's forum in regards to Ubuntu and Security:
http://www.leovilletownsquare.com/fu...php?tid/14463/