Toshiba Laptop turns on, but after restart, black screen.

So, my laptop was working just fine a couple days ago, but I noticed that it was lagging a lot and not responding, so I manually powered it off. Now, it doesn't display my home screen, no matter what I do. I've looked through suggestions, but they aren't working at all. My keyboard is working just fine, since I can press number lock and caps lock, but Ctr+Alt+Del doesn't work, nor does Sticky keys. Usually, my laptop says that it encounters a problem and restarts again, but when it prepares for automatic repair, it's taking forever for it to load. It seems like each time that I restart it, there's a new problem. For example, I reset it one time, and I had a black screen, but I had the cursor on the screen. Another time, it loaded, but there was nothing. My computer says that it will diagnose the problem, but it's taking forever. I kept my laptop on all night to see if it would load, but it was still the same in the morning. What else can I do without taking my laptop to an expert?