@AngieH91 , I'm sorry you're experiencing this. If the unplug suggestion doesn't work, I would try:
1. Clear the cache (fixes random reboots) 
Hit HOME 5 times.
FAST FORWARD twice. (Clears cache & tv reboots itself. Be patient. It takes 2-3 minutes for the tv to go black, and come back on)
You'd do that while the tv is on. You won't be able to see anything. But, there's nothing to see. Be patient. If you don't see the front light flash after at least 2-3 minutes, then you may not have done it right (waited too long between key presses, etc.). Try it again. You should see some front-light activity sometime during that 2-3 minutes which would tell you it recognized the key sequence.
2. If that didn't work. I would unplug the tv, hold the power button 30 seconds to discharge residual electricity. Then hold the pinhole reset button (back of tv) while plugging it in. Continue to hold it until the front light flashes and/or dims (15-20 seconds).
If your screen works after that, then I would tell the setup wizard that I'll setup internet connection later. This will use a smaller, maybe older, version of the software. You could play some HDMI content/games through it and see if the problem returns. If not, you could try setting up the network (home>settings>network) and see if the problem returns after that. (I have my two Roku tvs reset this way, and permanently disconnected from the internet to protect them from untested updates. I stream with an external stick through HDMI).
3. If none of that works, then I'd say it's a hardware problem. There are videos online showing how to fix problems like this. You might have to buy a tcon board, or something. It's pretty easy to do (it looks like).
 Roku has created some controversy about the so-called "clear cache" fix. They participated in a Business Insider article which seemed to be mock Roku customers about this (over semantics, "there is no cache. Silly customers!" [loose quotes]). The fact is: it actually does fix problems. If Roku ever got past mocking its customers, it might have time to actually diagnose and fix the underlying cause of the problems which that self-help operation actually does fixe. So, be prepared for someone to mock you if you ever refer to it as "clear cache." Whatever it is, it really has fixed problems other things didn't.
"People are often amazed at how much we’ve done with the number of engineers we’ve got." (Roku CEO Anthony Wood, Austin Statesman, Oct 4, 2019). "Amazed" is one way of putting it.