Q:  How can I check to see if there is a disk in the "A" drive?

A:

var
  ErrorMode: word;
begin
  ErrorMode := SetErrorMode(SEM_FailCriticalErrors);
  try
    if DiskSize(1) = -1 then
      ShowMessage('Drive not ready');
  finally
    SetErrorMode(ErrorMode);
  end;
end;