Actually I was considering giving her Windows XP. That runs pretty well now, and has less problems.
Windows XP was killed off in June 2008, last computer with it sold in 2010, mainstream support ended 2009, and Microsoft will fire the final shot on the 8th of April 2014.
So basically, you're wasting your time with XP. Particularly if you're not running XP Professional, as only the "business" editions are eligible for extended support..... XP Home, XP Media Centre etc. are already dead as far as Microsoft is concerned and you really should NOT be running them on any computer with an internet connection (even an intermittent connection).
Vista mainstream support ends 10th April 2012 and extended support until 2017.
Same note about non "business" editions applies to Vista... if you're only running Home etc.
Don't even think about running any version of Windows outside of its support period.... unless your computer is PERMANENTLY disconnected from the internet. I don't want spam from your zombie, thank you very much.