Kaz. On the back of your Laptop you should find a sticker. Look at it and find the serial. Google the serial (along with the words "Dell" and "drivers") and it should take you to the Dell support site, or a third party site, where you can then download the drivers for your laptop. I would download the lot, but you should, at least, download the drivers for your Audio, Video (Dispay) and Network Adaptors. That sould at least get yo up and running after you have loaded a new operating system.
Mind you (as others have asked) why are you doing it?