18 Audi q2l head-up display can't be turned on.

First of all, distinguish between monitor failure and graphics card problem (the indicator light flashes green because there is no signal). Put the fault indicator on another computer for testing. If there is something wrong with the monitor, please check the data cable and connector. If there is something wrong with the video card, please reinsert the video card and reinstall the driver. If there is something wrong with the graphics card, unplug it and plug it in again, and you can use it.