If the boot loader is stored on the SSD, I am not sure if you actually can simply move it over to the HDD, then remove the entry for Windows 8. Removing the entry is easy, moving the loader is the potentially hard part. Unless someone else can post a method of moving the loader to another drive, you're probably stuck reinstalling Windows 7.
This is why I always encourage everyone to install Windows with only one drive connected. You have to manually pick the drive you want to boot from if you want to go to the other operating system, but it's a LOT easier to clean up if you want to remove one OS (or add more) later on.