Zepprulz 0 Newbie Poster

Upgraded from win98 to 2000 professional on an HP Pavilion 6346. I am getting an error message that I am missing ethernet controller and video card controller. It will not read the network adapter. I have tried 3 different cards but no luck and of course I can not find the downloads for any of them online. Is this as simple as going somewhere and buying a new card or is there more to it? This is my first time upgrading a system and I thought it was going to be simple...