Upgraded motherboard…

I have a machine with Win2K, and it works fine. In upgrading the motherboard, CPU, and memory, I am getting a Blue screen error that says INACCESSIBLE_BOOT_DEVICE. The hard drive does recognize my HD without a problem. The HD Controller is a UDMA/66, and I have had this problem with another motherboard, but I really need to get Win2k to recognize the controller. I tried Safe Mode, and get the same error message. I get the Win2K logo screen, and the error message.
Any help would be appreciated.