That’s why its always advisable to show all file extensions in Windows.

As soon as you open the txt file, it’ll execute the exe file and the file will spread the virus in your computer. If Windows is set to hide file extensions, you’ll see the file name as filename.txt and you’ll never know that the file is actually an executable. Its very easy to mask an EXE file as TXT or any other filetype by renaming the file to. In my opinion this feature to always show file extensions should be enabled by default as it might be a big security risk. Once you disable the option, Windows will start showing almost all file extensions and you’ll be able to distinguish between different file types. Just disable “ Hide extensions for known file types” option in Folder Options. You can enable this feature using Folder Options. But Windows allows you to show these hidden file extensions.

It is done to make user experience easier so that the user doesn’t get confused by various file extensions. By default all Windows versions such as Windows XP, Vista, Windows 7 or Windows 8 don’t show file extensions for known file types such as exe, mp3, txt, doc, avi, etc.

How to view file types in the name