To turno on compatibility mode, you must right click on the link to Paradox, click on Properties, then click on compatibility, then you can activate compatibility mode and choose which versione of windows you want to emulate.
Besides that, if you have the non-delivered forms, reports and scripts that constitute youre paradox application, you can recompile them in ALL subsequent versions of paradox, yous by opening them and saving them again.
I'm totally sure (by personal experience) that Paradox v 9 and up run perfectly well under windows XP, except for a single bug about selecting a db server alias in the open dialog which appears on XP SP2, but is solved in latest pdox v11.