Problem playing SD2 games

[packer]

why doesn't xp show the file ext code anymore? e.g.


used to be like say Dflw.exe now it is only Dflw

but in the file description area it will say it is an application

Is there anyway that xp can show those file extenions. THe other reason i want them is to change them so that the computer doesn't recognise them( important files )