I just bought a 2TB external memory disc and when I conect it to my computer it saids that the external disc only has 29.2 GB of memory. It is incredible is brand new
Have you try reformatting the drive? You can use DLG to erase and test the drive.
Have you checked the jumber settings on your hard drive? This link might help you:
http://www.techpavan.com/2009/04/29/hard-disk-capacity-limits-to-32-gb-solution/
regards