Computer help: Is it possible to delete an empty partition?

Is it possible to delete an empty partition?

Here is the background;
Hardware:
Lenovo Ideapad Y510
Processor Intel(R) Core(TM)2 Duo CPU T5550 @ 1.83GHz
Memory (RAM) 4.00 GB
Graphics NVIDIA GeForce 8600M GT
Gaming graphics 1535 MB Total available graphics memory
Primary hard disk 5GB Free (29GB Total)
Total hard disk is 250GB, with 29GB to C, 187GB to D and another 17.65GB empty and and not connected to either drive.
Software:
Windows Vista Home Premium
32-bit operating system

Now here is the question, how can I safely delete and combine the empty space to the C drive? I have looked at deleting the empty D partition using disk management, but have read others on here say that once you delete the drive the empty space does not get attached to the C drive, but just remains an open space. I really don't understand why manufactures are doing this to the drives, having a small space on primary and all your space on a secondary. Why not just have it all on a single drive like it used to be. Both D and the open space are showing at 100% free. Thanks in advance for any help.