Title: Detect if sound card is present
Use WaveOutGetNumDevs procedure. It returns number of waveform-audio output devices present in the system.
Don't forget include MMSystem to uses chapter.
uses MMSystem;
...
procedure TForm1.Button1Click(Sender: TObject);
begin
if WaveOutGetNumDevs<>0 then
Label1.Caption:='Sound card is present'
else
Label1.Caption:='Sound card is not present';
end;