>I want to delete all files is a user chosen dir. I use ADIR() to get a file listing and the command DELETE FILE .... to delete each file using a FOR ... NEXT loop.
>But this fails when it encounters a hidden file.

You can change the file attributes using an API call, and then use the DELETE FILE or ERASE command. There's sample code here on UT under Win32 and other APIs showing how to change file attributes.