Help: Wd 3Tb Drive Only Showing As 700Gb (Not 2.1Tb)

I just got the WD 3TB Green HD and when I put it into my 49x HP it only showed up as 700GB instead of 2.1TB. Any ideas as to why or what I should do to access at least the 2.1TB (going to try the 3TB WHS hacks).

Many thanks in advance for any advice,
Todd