my fren having problem with dota 2. he say his valve video cannot load, black screen and distorted sound, the he press esc then go to loading screen, later he say freeze or CTD liao.. his pc is win7 and just bought recently, decent spec with dedicated card. anyone know how to solve this problem?

he redl edi.. i now ask him do clean redl from forum.. ya laptop .. asus one but i think gt640m like tat i5 or i7, wont be bad right? i go dev dota forum also saw similar case but no reply at all..