Hi can anyone help Me?

I bought a Dell Dimension 8400 about 6 weeks ago, with it I got 250 GB hard drive. Now whenever I click on Local Disk (C: ) It shows that Total size is 229GB and I’ve got available 214GB Free memory, I don’t understand how that could be when I’ve only used 4GB with all my  documents and programs, should it not show that iv got 246GB available memory. Is that normal? Is there anyway that I can find out where the other 32GB memory is being used up and how to I rectify this problem. All suggestions and comments will be greatly appreciated.

Thank You

SaintSam