Transporting a Windows OS between motherboards is tricky. This site has several methods you can choose to try and move the install to new hardware. Usually the key thing is to uninstall chipset specific drivers for the IDE controller before changing the hardware. The error you are getting means 2000 loaded it's storage driver, and can't see the hard drives. Most likely your motherboards use different IDE controllers, but the generic 2000 driver should support both.