Well if you didn't save your original CD with the original drivers... you hope HP.com has a legacy section and has the driver for you to download. Your second option is, find the the LAN chipset and go directly to that vendor's site and again try to find the driver. Last option is, maybe is the easiest after all, hopefully an eBay seller has the original CD to sell.
You can find the ethernet\LAN and wireless drivers under Driver-Network. Sorry I can't tell you which one will work right off the bat, you'll have to do some leg work and try them out one by one. You can safely avoid the bluetooth drivers for the time being.