a folder in DOS you will have to use the "Deltree" command,
for example to delete the windows directory you type:
then be prompted for a Y or N answer
“Y” and enter will start the deletion of the folder and all
it’s contents, including subdirectories this will take several
minutes, when finished it will be gone.
“N” and enter will cancel the operation.
command is irreversible, so be careful in its deployment