Vérifier s'il y a une disquette dans le lecteur

function DiskInDrive(Drive: Char): Boolean;
var
ErrorMode: word;

begin
{ make it upper case }
if Drive in ['a'..'z'] then Dec(Drive, $20);
{ make sure it's a letter }
if not (Drive in ['A'..'Z']) then
raise EConvertError.Create('Not a valid drive ID');
{ turn off critical errors }
ErrorMode := SetErrorMode(SEM_FailCriticalErrors);
try
{ drive 1 = a, 2 = b, 3 = c, etc. }
if DiskSize(Ord(Drive) - $40) = -1 then
Result := False
else
Result := True;
finally
{ restore old error mode }
SetErrorMode(ErrorMode);
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
if DiskInDrive('a')=false then
begin
ShowMessage('Drive not ready');
end;
end;