Confirm the system of your computer/laptop is windows7/8/10,it does not work for other systems(linux,chrome os).
2.check your usb port if it is loose or not,and change another port to try.
3.if found it can't convert high quality pictures on your monitor, please check if you plug the adapter on a usb3.0 port of your computer or not.
4.if your computer/laptop have usb 2.0 port only, don't buy this adapter. it does also works usb 2.0 port, but for usb 2.0 port the max resolution support 800*600 only.
5.both hdmi and vga output supports video to monitor/hdtv. hdmi also supports audio output, but vga doesn't have that capability.
6.please ask for help if you tried all the above still can’t get it work.usb to hdmi vga adapter, usb 3.0 to hdmi converter 1080p hdmi and vga sync output support windows 10/8/7 only (black)