I have a question concerning XP. I read someplace, but I forgot where, that uninstalling " Internet Explorer" is also a good idea, if you are keeping Windows XP. When I went to uninstall it, a popup said, all the programs installed after having Internet Explorer may not work. Well that is all the programs on the pc. It seems odd, because it is only the browser Internet Explorer which would be uninstalled.
Not trying to highjack your thread.
Read about the topic here:
http://pcsupport.about.com/od/browsers/f/removeiexp.htm
Basically, explorer is hardwired into Windows and provides other services also, so it is not easily removable. I distinctly remember that MS did it on purpose to circumvent anti-monopoly court ruling that ordered them to provide Windows without Explorer as an unfair advantage. It was not technically possible, so they offered two versions - one with Explorer that worked, and other without Explorer that did not work.
However, there is a solution to your Explorer woes - migrate to Lubuntu. It's very lightweight, you will be able to run it on old hardware, and lastly - no Explorer, not a trace 
