hey you can do lots of things to make space on c: drive.
1. Uninstall any programs which you dont use.
2. Do disk cleanup
Right click on the c:\ and click on properties then click on disk cleanup button.
3. Delete files which or not of importance to you.
4. Music/ video files such as mpeg, mp3, jpeg etc etc write it to cd's and delete it from the computer harddrive.
this should help.