Step 2) Accessories -> System Tools -> Disk Clean-Up
Now the Disk clean-up window should have appeared and it will be calculating Just wait for it to finish
Step 3) Once the calculation has finished a new window will apear and you can chose what files to delete. Select which files you want to delete and click Ok.
Step 4) Now you will get the sign are you sure you want to peform these actions hit yes. Now the final window will open up and it will say cleaning up drive c, Just wait for it to finish and your done.