Upgrading to XP Pro won't do anything for you. Windows XP (either home or
pro) is an *operating system* - a core platform that does all the system
level stuff like managing disks and monitors and mice and printers that
makes the computer compute. Programs like Word are *applications* -
programs that run on top of the operating system and do the useful things
you like the computer to do for you, like writing letters or making videos
or playing games. It's unfortunate that MS chose to use the marketing term
"XP" for both Windows XP, the operating system, and Office XP, the suite of
applications that includes Word, Excel etc, because the similar name
confused a lot of people into thinking that one was part of or required the
other. They really are competely different classes of software, totally
separate, and you can happily run Office XP on a Windows 2000 system or
Office 97 on a Windows XP system for example without much difficulty.
If you want to use MS Word without paying the cost of upgrading to the full
Office 2003 package. take a look at MS Works. It's a simplified set of
applications for the home user and it includes MS Word, the same one as with
the full Office suite, as its word processiing component.