I would suggest you get a CD copy of Ubuntu and run it so that you can
try it before you install it. This will load and run fully in memory.
Then when happy just click the icon to load fully. You can dual boot
with your current system, either XP or Vista or if brave have it delete
the whole drive and clean install. It is likely to run most of your hard
ware at once but Linux drivers are readily available. It comes with Open
Office and lots of other software that you may well find are equal to
MS. Later you will find out that some things are compatable.