Asus Taich not able to display my 25" external monitor

I have asus taichi. When i first bought this it was working fine that i can extend to my external 25" monitor but the mouse has been an issue pausing and stops alot. I went and did an upgrade on the program and now the icon from my lower hand side of the display is gone and my external monitor can’t be connected. I kept on connecting to my dual display as my external monitor.