Win2K doesn't support ATA100, and it will default ATA100 HDs to PIO4 instead (bug). If you have a Intel Chipset or a Promise card this doesn't matter because Intel has drivers to fix it, and Promise makes Win2K think all the drives are SCSI. However with the VIA chipset youll need to download the software for your HD and switch the HD itself to UDMA4 (ATA66) instead of UDMA5(ATA100) Then it will work fine.