Did the 1TB drive previously have a boot/system partition on it? If so, the BIOS boot order might have been trying to boot any system previously installed on the 1TB drive and that is why it wouldn't boot (crashed bug check). I presume since you're running Windows 7 that you have Secure Boot feature disabled and using Legacy BIOS mode.
If you can get into Windows again, the disks might not be receiving a drive letter or online which you can assign from Disk Management (Control Panel -> Administrative Tools -> Computer Management -> Disk Managment).
Are the drives detected in Windows Device Manager? Also check SATA port configuration in BIOS, some BIOS permit disable/enable individual SATA ports or controllers.