Well this might be the case of Windows temporary files which automatically gets created when you are working on Windows.
NOTE: This process will work on Windows XP,Vista,7 and 8 and it is completely safe. However, you are advised to save any work and close your work sessions so that it can free up more space.
Some of these very simple steps will help you to clean up the junk files from your PC. So let's get started.
1.On your keyboard press: Windows Key+R
2.RUN Dialog box will appear as soon as you do that.
3.Type in the name field "%temp%" (without any quotes)
4.Now here you will see all the temporary files which are created by Windows.
Screenshot:

5.So on your keyboard press CTRL+A to select all of the folders.
6.Now delete them permanently press SHIFT+DELETE on your keyboard.
WOW ! All the junk files are deleted.
Congratulations! You have some more space on your Hard Drive.
Advice: Do this process atleast once in a week so that you can never get out of free space on your Hard Drive.
Hope this helped you. Thanks for checking out my tutorial.
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