Use a partition manager such as EASEUS Partition Master or Paragon. May I presume your D partition is for data? If D is the CD-RW or DVD-RW, no you can't.
Figure how much you need for Windows + your programs, by looking at the properties of your partitions now. But 64 GB would be far too much, leaving not enough for data. But if you miscalculate, you can always change it at any time.