|The easiest way to free space is just to delete movies, music, pictures - anything in "My Documens" since they are most likely to not be essential files. Just make sure you know what you are deleting.|
Or else you can simply buy another Hard Disk Drive.
-If you get an internal hard drive then you may need some help installing.
-If you get an external hard drive then you can just plug it in and cut/paste large, unnecessary files that you do not want to delete.
Disk Cleanup and Defragmentation will probbly not make much difference to the percentage of free space you have.