New HD in an old computer

[siccjay]

When I built my new comp I put my old HD in it. I recently told a friend I would give him my old computer but he would need a HD. He found a HD and we put it in my old comp. We reformatted and got Windows XP running but neither the soundcard or modem are showing up. The soundcard is onboard and worked when I stopped using that computer. I don't think there is anything I unhooked. The only thing different is I switched out the RAM.

Is this a common problem? Anyone have any idea why this is happening or how to fix it? Let me know please. Thanks