first, open my documents and go to tools, folder options.
then go to tab view and untick "Hide extension for known file types" and apply.
it is useful when u want to email someone with extension like .exe, .dll because email will detect it as a virus. with this changes, it can bypass email security.
example:
in my case i need file JInitiator from my friend and email it to me. the file is jvm.dll and easily change it to jvm.txt after i download it, i change back to jvm.dll. not a big problem.
bacteria comment: only download and open with file u already know whos your sender is. :D
