As you know, Windows XP is EOL now. However, I'm still using that machine I assembled in 2003 as my only Windows computer, and I don't plan to change that. So I went ahead ans upgraded it to Win7.
Everything works fine, except the video card. Windows will complain that it needs a DirectX9 card. I know such a thing can be found even for my old AGP motherboard, but that's more money than I want to spend.
AMD won't provide drivers for such an old card for the new windows (Vista and 7). You can force-install the XP driver, and it will mostly work, but the system will BSOD on shutdown. Not so nice.
The solution is simple, once you have found it. The drivers for Windows Server 2008 will work perfectly. In the case of my Radeon 7000, these can be downloaded from Dell's FTP.
Note that the installer won't work, but using the inf files provided with the driver will go fine. And I now have my PC running as it should again.
I should look into Windows Server drivers for more of my hardware. It looks much less bloatware-enabled than the mainstream versions and gets the job done.