Hi mikes1992
It is possible your second partition (D
was or is not a primary partition (it says Logical in the picture) and you reduced the size of a logical partition inside an extended partition but did not reduce the size (start point) of the extended partition.
You may have to remove the second logical partition then the extended partition, then expand the first partition (C
then re-create the second partition (D
I would use Parted Magic (or GParted) Linux boot disk to sort out the problem.
best of luck
Mike Barnes