Wow! I didn't know Packard Bell

is still in business. Anyway, you need to find out all the hardware components first. And then download the necessary drivers and install them. Here is a tool which can identify a lot of hardware components.

http://www.cpuid.com/pcwizard.php

You don't have to register that copy of Windows XP. Search the internet and crack it since you cannot find the origianl serial# or key.

Don't try to install the whole OS youself unless you want to experience something new.