partition resizing

I have a 20gb hard drive. C drive is 1gb and D drive is 2gb. I have windows installed in C drive. Now the drive has only 120MB of free space whereas my d drive has 1.5gb. I wish to increase the size of my C drive to 2gb fron 1gb and reduce the size of my d drive to 1 gb from 2 gb.

How to do this without losing any data or resorting to the reinstallation of windows and other application files.