A few points. Windows 2000 is at SP4 and more critical updates. Windows 2000 and the DVD drive doesn't use any CODEC to read files from the media. You may have meant to ask about DVD Video playback, but that's not supported in Windows 2000. For that you install your DVD player software. Microsoft didn't supply that.
I have reformat a Windows 2000 SP3 computer's hard drive, but now the DVD drive can only read DVDs less than 4GB, any DVDs above 4GB cannot be read. Before reformat, no problems.
What could cause this; wrong DVD drive drivers, wrong codec, wrong BIOS settings?
Any ideas shall be appreciated.