I was playing a video game, when it crashed and my computer lagged, and i couldn't do anything, so I held down the power button to turn it off. When I restarted, it showed the Dell startup, the windows logo, then just a blank screen. I have now restarted many times, and occasionally, the mouse shows up. Putting it in safe mode was very difficult (my computer boots quickly), and it didn't seem to do anything.
Please explain how to do things thoroughly (most of what I know is from experimentation, but I don't want to mess anything up), and I would like to keep the data that I have.
I am using Windows 10, 16 GB RAM, Dell XPS 8300.