casanova,
Oracle 8i installs on windows XP and works fine without any issues. No idea what ur talking about. As for the system being slow, mate your installing a database so obviously its going to be slow. The versions of Oracle one installs doesnt really matter. You should have atleast 512MB RAM if your going to install a database.
The only difference between personal Oracle 8 and the enterprise version is that I can create only one instance of the database in personal Oracle 8. Apart from that nothing more.
Mitesh,
Could you please be more specific as to what you problem is ? I have installed de-installed Oracle loads of times on different OS'es. Provide as much details as possible please as to what problems you face.