I know a way that can help you. We can use the dos command to stop the windows to restart. I will tell you the method by the screenshot.
The first step:
input cmd command after you open the start command box.
The second step:
then you can see the dos window, now you should press the shutdow -a command and press the enter key ,then the window will disapper and at the right buttom of your computer you will see the prompt information
that you have cancled the restart plan. That's all, Hope can help you!