Windows 7: SATA Drive causes a reboot loop

Running Windows 7 64b RC on a new Gigabyte MB, 4 GB ram AMD 955 CPU. I have two SATA drives on system C: (OS) D: (Data) and trying to install another SATA drive for additional storage a Hitachi Deskstar 165GB. Once this additional drive is connected, the system is in a constant boot loop. System will boot but not recognize this HDD when connected thru a sata to usb adaptor. If I move it to my XP machine, it is recognized and works just fine whether sata or usb connected. I have removed the D: and tried to install this alone with the C: ...same problem. There are no jumper pins etc on this Drive, I have tried both the sata power connector and the regular Molex power connector..looking for ideas... Tx

In BIOS, is the drive "C" selected as your first disk?

Is the offending disk bootable?

The Hatachi drive is not bootable, when I connected it to my XP machine last, I copied all the data files to a folder on my XP C: and reformated the Hatachi, then copied all the data files back from the XP machine thinking there might have been something wacked up. ??

From the BIOS:
Chnl 0 Slave IDE CD ROM F:
Chnl 2 Master Sata 1 D: (Maxtor)
Chnl 3 Master Sata 0 C: (WDC)
Chnl 3 Slave DVD Sata 3 G:

HDD Boot priority:
1 Chnl 3 Master WDC
2 Chnl 2 Master Maxtor

1 New 750W PS...

Tx for you input!

Anybody??

Well I still do not know the reason, but the cure was to go into BIOS and change the option to stop on error. It was configured to boot up, regardless of error, which it did and has worked fine since. Review of the event logs revealed nothing related to the HDD (that I can see) HDD is useable both when connected directly to the sata cable or thru a sata to usb device.