You should have installed Windows 7 with the SATA configuration set to RAID. Use the add driver feature in the beginning of Windows 7 installation to add the IRST (Intel Rapid Storage Tech) driver. Single drives are allowed in RAID mode. Just plug the drive in.
It is possible to change the configuration after installing Windows 7 by changing some registry settings. Microsoft has an auto fix to automatically change the registry settings. You will need the IRST driver.
Error message occurs after you change the SATA mode of the boot drive