1
Your description of the problem indicated the graphics drivers crashed on your system, do you regularly go to the Dell website to ensure all your drivers are fully up to date, what would stop Windows updates installing drivers.
2
In general Windows updates only install on the second Tuesday of each month, and when an update is ready to install, you should see a notification at the bottom right of your screen indicating your PC will restart, on that notification, you can choose not to install the update now if you are performing any important tasks on your PC.
Also, if you go into the advanced options of Windows updates, you can set active hours for when you do not want Windows updates to install on your PC.
3
Currently there is no working method to stop the updates installing on your PC, but there is an update being released soon that will allow you to pause updates indefinitely on your PC.