How to recover disk space

HI I HAVE A LAPTOP WITH c DRIVE PARTITION IS 19.9GB. I had uninstalled Norton Ghost from my hard drive. I moved some of the directory which used more to disk space to another partition and deleted some of the unnecessary files. AFter empty recyclebin still disk shows very little free disk space. I want to recover the all the free space on my C Partion. Is there any tools to check and recover the free space. I did defragment that didn’t helped me.
Thanks
Shivaram