If I upgrade from XP Home Edition to XP Professional,
can I go back to XP Home Edition if I do not like XP Professional.
The two versions operate on the same code. The Pro version has
additional features, but nothing you couldn't get from freeware.
Unlike most other OSes, you may run into Microsoft validation issues.
If you have extra money, why not spend it on something you need or can
use? A wireless mouse or more memory, perhaps?