S7562 mt6575 dead after flash.

S7562 mtk 6575 dead after flash, I tried many firmware to recover mobile but mobile still dead, one thing I seen which is that sp tool detect mobile as mtk USB port but da USB vcom driver not connec properly I already uninstall driver and installed again even in another PC same problem appear. Device manager yellow mark show at da USB vcom driver.

How I can alive mobile ?