when you install drivers, files go in variosu location buts mostly they are in the system32 folder of your Windows directory.
I dont suggest you go and backup that directory since it also contain a LOT of things crucial to your system.
You system might be unstable if you put a used system32 folder into a freshly installed Windows installation. I suggest you just collect all the driver you need and install them the correct way. This will reduce any problems that you may have later. Though usually XP has default drivers for most things so all you really need is your graphics card driver, possibly the chipset driver, and maybe your sound card driver if you have a dedicated sound card.