BorderStyle := bsNone;
WindowState := wsMaximized;
//======================
BorderStyle := bsNone;
Left := 0;
Top := 0;
Width := Screen.Width;
Height := Screen.Height;
//==============================
BorderStyle:=bsNone;
SetBounds(0,0,Screen.Width,Screen.Height);

（出处：DelphiFans.com）