1. Uninstall programs that you no longer use anymore. From the Control Panel (in the Start menu), open a program called 'Programs and Features.' This will show you every program that is installed on your computer. Go through this list, find programs that you no longer use and uninstall them using the 'Remove' button at the top of the window.
2. Delete any media files you no longer use as they take up a lot of room on your hard drive. Go through your media file collection and delete anything you no longer listen to or watch. Or, you could back all this content up onto an external hard drive or USB flash drive. This will get everything off of your main hard drive, freeing up as much space as possible.

3. Compress your 'C' drive. Open the 'Computer' folder (in the Start menu) and right-click your 'C' drive icon. In the 'Properties' window for this drive, check the 'Compress' option and click 'Apply.' This will compress all the files contained on the drive, freeing up as much space as possible and ensuring that you don't see the not enough disk space error for the foreseeable future.