What are the sizes of the drives you have successfully installed?
What is the history of the 320GB drive? How does a utility such as HD Sentinel detect it? How many LBAs/sectors does it report?
The D630 is currently running perfectly on an 80gb drive, and I'm convinced it's an issue with the drive, not the D630.
The WD 320 drive was in an HP/Compaq 6910p and never had any problems. When I swapped the drive to the D630 to reformat and install Windows, etc, it just recognized 75gb. Since my post of last night, I used an adapter to connect the drive to my desktop and used computer management to view the properties of the drive. Sure enough, it shows partition as MBR, capacity of 74873mb.