Create An Undeletable Folder

1) Goto Start-> Run, then type cmd to open command prompt.

2) Suppose you want to create a foldet under "C:" drive.

3) Then type the following command and press enter 

md \\.\\c:\con

4) Here the folder name is "con" and normally you can not delete this folder.

5) If you want to delete the folder then type the following command and press enter

rd \\.\\c:\con

NOTE = You can not give any other name to the folder except the following names

CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9