If you want to reduce the number of unnecessary files on your hard disk to free up disk space and help your computer run faster, use Disk Cleanup. It removes temporary files, empties the Recycle Bin, and removes a variety of system files and other items that you no longer need
Click on Start –> All Programs –> Accessories –> System Tools. Then click on Disk Cleanup. Alternatively you can open Start Menu and search for Disk Cleanup.
Once open, select the drive you want to clean up. Mostly this will be the drive where you have Windows installed. Select C:\ drive.
Let Disk Cleanup determine which files can be cleaned up.
You will then see a dialog with the files that can be cleaned without any harm to the system. Select the files that you do not need and click OK.
If you have admin access, you might want to clean up system files as well. Click on System Files in the above dialog. You will then see a More Options tab which you can use to remove old system restore points and shadow copies.