Shazzam,
ME was Windows running on DOS, Remember? XP comes from 2000 which came from NT4 blah blah blah......... NT's code writers came from the Digital Equipment Corporations employees. VMS once owed by DEC sold to Compaq and then HP who now owns the rights. VMS is very much like Unix in many ways, but the bottom line is that it isn't DOS. There should be no comparison between ME and XP, they are not in the same game.
If you want to try Linux, there are some great distro's out there!!! But if you're not very savvy with how a PC works, then I would suggest you try one of the lessor command line driven versions. And go for a well developed GUI. SUSE is an awesome system as well as Fedora Core. Ubuntu is nice, or Kubuntu with the KDE Desktop which I prefer to Gnome. But that's just my preference. And all of it is free!!
And yes, it will allow you to have a dual boot to XP. Just keep in mind that you will have to replace the NTDLR (Master boot record is lost or overwritten by the Linux bootloader) should you decide to remove Linux later. Best thing to do is to have a second hard disk in the machine and plug it in whenever you want to run Linux, until you decide what you would like to do from there.
Good Luck!! :)
mac?? You get those at McDonalds don't you?? :)
Sorry Pete!! Couldn't resist!! :)