How do I change the System Partition?

http://i49.tinypic.com/2w7i9ft.png

I want to be able to safely remove the D: partition in the image linked above. I can tell that I will need to change the Z: partition into the System partition to do so, but I cannot find out how. Please help! Thanks in advance.

Could you be a bit more descriptive? What is are you trying to accomplish?

Didn't I already provide that information?

This is not a stupid question.

We need to know if you are dual booting.
We need to know if you no longer want XP or Vista.
We also need to know if you are planning to install Windows 7.

Mainly we need to know if you have XP on the first partition and Vista on the second. The best I can tell you have XP on the first partition and installed Vista to the second partition. It also looks as if you are booted into Vista which is on the second partition and removing D: would remove Vista.

Is this what you are wanting to do? Or do you have everyone confused from lack of detail.