How to use the cmd command to delete files that are not used by win7 system

There are some files that are not used by ordinary users in Win7 system. How can I delete these files and expand the memory of the system? Now Xiaobian teaches you an easy way.
Recommended: The latest Win7 download
Solution:
Click the Start button, enter cmd in the search bar, right click to select “Run as administrator"

In the popup In the dialog box, type “rd/S/Q c:\\\\WINDOWS.OLD or rd/S/Q $WINDOWS.OLD ”
When you are prompted to confirm the deleted target WINDOWS.OLD folder, confirm the input y and then Press the Enter key.
The above is the way to delete files that are not used in Win7 system. If you don't want to waste Win7 system memory, then delete these files that you can't use.