Missing Drivers

Hello,
I have a major problem here. I finally turned on my cpu after about 6 months, and a good chunk of drivers are missing. Heres the thing, my grandpa built the computer for me. I gave it to him to do a small repair, and add a dvd drive. Well, after he gave me the computer back, I had a bunch of things going on, so I didn't have time to even plug it in. In the meantime, my grandpa was diagnosed with cancer and has since passed away. I have no idea how to get my computer up and running again. I am missing my Ethernet Controller, my Multimedia Audio Controller, my USB Controller, and my VGA Video Controller. It wouldnt be so hard to figure out if I was able to get an internet connection, but I cant. What can I do? BTW i have Windows 2000 on it