uses
  Registry;

type
  TInstallationPlace = (le_None, le_CommonDesktop, le_CommonProgs, le_CommonStart,
                                 le_UserDesktop,   le_UserProgs,   le_UserStart);

// check whether a shortcut or a file with name s is either on
// the desktop, in the start menu or in its programs submenu.                                  
function LinkExists (const s : String) : TInstallationPlace;
var
  cDesktop,
  cProgs,
  cStart,
  uDesktop,
  uProgs,
  uStart : String;

  function myExists(const s : String): boolean;
  begin
    // s can be directory or a file, so FileExists() won't do it..
    myExists := FileGetAttr(s) >= 0;
  end;

begin
  // check whether we have the link in All_User's Desktop!
  cDesktop := '';
  cProgs := '';
  cStart := '';
  uDesktop := '';
  uProgs := '';
  uStart := '';
  with TRegistry.Create do
  begin
    RootKey:=HKEY_LOCAL_MACHINE;
    if OpenKey('\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders', false) then
    begin
      cDesktop := ReadString('Common Desktop');
      cProgs   := ReadString('Common Programs');
      cStart   := ReadString('Common Start Menu');
    end;
    CloseKey;
    RootKey:=HKEY_CURRENT_USER;
    if OpenKey('\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders', false) then
    begin
      uDesktop := ReadString('Desktop');
      uProgs   := ReadString('Programs');
      uStart   := ReadString('Start Menu');
    end;
    CloseKey;
    Free;
  end;
  // check in all 3 places for our link
  Result := le_None;
  s := '\' + s;
  if myExists(cDesktop + s) then Result := le_CommonDesktop
  else
  if myExists(cProgs + s) then Result := le_CommonProgs
  else
  if myExists(cStart + s) then Result := le_CommonStart
  else
  if myExists(cDesktop + ChangeFileExt(s, '.lnk')) then Result := le_CommonDesktop
  else
  if myExists(cProgs + ChangeFileExt(s, '.lnk')) then Result := le_CommonProgs
  else
  if myExists(cStart + ChangeFileExt(s, '.lnk')) then Result := le_CommonStart
  else
  if myExists(uDesktop + s) then Result := le_UserDesktop
  else
  if myExists(uProgs + s) then Result := le_UserProgs
  else
  if myExists(uStart + s) then Result := le_UserStart
  else
  if myExists(uDesktop + ChangeFileExt(s, '.lnk')) then Result := le_UserDesktop
  else
  if myExists(uProgs + ChangeFileExt(s, '.lnk')) then Result := le_UserProgs
  else
  if myExists(uStart + ChangeFileExt(s, '.lnk')) then Result := le_UserStart
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  if LinkExists ('SourceCoder') <> le_None then
    ShowMessage('yes')
  else
    ShowMessage('no');
end;