Took a quick peek at this yesterday. Are your SATA ports set as AHCI? I understand you are using the IDE connection for CD/DVD.
So ensure the SATA ports are configured as AHCI, And SATA ports set as type... Moving the second disk (160GB) to ports 5 or 6 above may also help. Now the caveat, if you had the Toshiba (500GB) set to IDE Mode instead of AHCI when windows 7 was installed, you may have issues booting after changing the southbridge controller's operate mode from IDE "emulate" to AHCI. Give us an update about this and we'll try and help you move forward.