Code:

function SearchForText_AndSelect(RichEdit: TRichEdit; SearchText: string): Boolean;

var

StartPos, Position, Endpos: Integer;

begin

StartPos := 0;

with RichEdit do

begin

   Endpos := Length(RichEdit.Text);

   Lines.BeginUpdate;

   while FindText(SearchText, StartPos, Endpos, [stMatchCase])<>-1 do

   begin

     Endpos   := Length(RichEdit.Text) - startpos;

     Position := FindText(SearchText, StartPos, Endpos, [stMatchCase]);

     Inc(StartPos, Length(SearchText));

     SetFocus;

     SelStart  := Position;

     SelLength := Length(SearchText);

   end;

   Lines.EndUpdate;

end;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

SearchForText_AndSelect(RichEdit1, 'Some Text');

end;