Now you should go through and look for programs you don't use any more. There are usually programs that you download off the internet and install, onlt to find out that the program is completely worthless. The programs are just taking up space and can be removed. This wizard is actually a good place to start when removing programs. Don't be afraid to get rid of unused programs or crippled programs.
Most programs come with easy uninstall programs that rid itself of the program altogether.
After you've cleaned your hard disk of unused programs you should also clean your hard disk of old files you've downloaded off of the internet. You should be able to do this easily by going through your downloads directory. Most Internet browsers can do it automatically with the press of a button in your browser's settings. This has been known to clean from a couple of Megs to hundreds of Megs of disk space. The most important thing you should run on your hard disk is a Defragmenter.