Measurements of $BR(b \to \tau^{-}\overline{\nu}_{\tau}X)$ and $BR(b \to \tau^{-}\overline{\nu}_{\tau}D^{*\pm}X)$ and upper limits on $BR(B^{-} \to \tau^{-}\overline{\nu}_{\tau})$ and $BR(b \to s\nu\overline{\nu})$