I recently purchased a Inspiron 1720 with two hard drives (320 x 2) and am trying to partition the second hard drive into three drives of about 100gbs each.  I tried to shrink the drive by 102 gb (originally the disk management utility said I had about 305 gb available) so as to have a 202gb partition (which I would then shrink in half to give me two 101gb partitions in additon to the first one of 101gb).  However, I was unable to do anything with the 101gb of unallocated space so i reformatted the entire drive and now i only have 298gb available.

 What is the best way to recover the now missing 7gb and format the drive into 3 equal partitions?

Also, why isn't the full 320 available?