How to expand the capacity of the C drive under the Vista system

I used the Vista system, I did not expect the capacity of the C drive 20G is not enough, now only 2G. Is there any way to expand the capacity of the C drive? I have used magic partitions, but not. My hard drive is 160G, please help! Thank you!
[Answer]: Vista's compatibility with PQ8 is not good, you can try to use Acronis Disk Director Suite 10, your C drive 20GB is really a bit small. In Vista's disk management, you can adjust the disk capacity by compressing the volume and expanding the volume. If you haven't sorted the disk in advance, the capacity that can be split is small. Moreover, to achieve the extended volume, you must require the unpartitioned space to be in close proximity to the C drive, but the C drive is the first partition, so the space compressed by other partitions cannot be adjacent to the C area, so it is not used. It is recommended to use Acronis Disk Director Suite.