Default Find every files on your Pc by Editing regedit
Windows searches only for file types it recognizes. Files that aren't listed in the 'Registered file types' list are ignored (to view this list, open Explorer, choose Tools, Folder Options, and click the File Types tab).
So while 'Read_Me.xyz' may be a perfectly good file name to you, Windows pays it no mind because of the unrecognized '.xyz' file extension. Fortunately, a simple edit of the Registry will make Windows search for every file, regardless of its extension. Open the Registry Editor as described above,
and then navigate to and select HKEY_LOCAL_MACHINESYSTEMCurrentControlSetContro lContentIndex. Double-click the FilterFilesWithUnknownExtensions icon in the right pane, change the 0 in the 'Value data' box to 1, and press .