Also there is always the Free Open Source Linux Operating systems..

my favorite so far is Simply Mephis
http://www.mepis.org/


Linux free Operating systems {OS} info and sites

http://www.linux.org/
http://www.ubuntu.com/

variety of info on all OS -
http://www.computerhope.com/os.htm

I use both Linux and XP on my computer depending on what i am doing...
With dual boot system - You can choose which OS to load at start up. XP or the Linux OS.

It took me awhile to find the Linux OS's that recognized my wireless card without me having to anything.
Dlink - WDA-1320
The above card was recognized right away on my system by Ubuntu, Kubuntu, Simply Mephis, and a few others but these are my favs so far.