Black screen after startup - Dell laptop

I've been running into a problem lately with my dell laptop (windows 8.1). I updated my graphics driver using the nvidia software and got a black screen after start up and can't access the desktop.

After trying many of the repair options, I found I could get it working if I "refreshed" windows. I guess this removes all driver updates because my graphics were worse than ever. I tried updating the driver again and had the same problem, used a system restore point this time. I tried updating again, manually this time, and it worked. I think I somehow did it without restarting.

Today my computer restarted unexpectedly and now it wont boot up again. I'd love to know what's likely wrong with it (graphics card failure?) but I'd especially like to know if there's a way to work around this problem - as it was working for days before the restart I have to wonder if that's possible. My warranty also just expired, of course.

Thanks so much for any advice offered