Please help... “ The user profile service failed, user profile cannot be loaded’

I’ve been trying to fix this problem all day but nothing helps. My body is shaking and I’m worried sick. This is my only PC and I need it so badly. 

It took forever to load at the first, then it brought us to a temporary account. We followed some video instructions and then again restarted but now it says that ‘the user profile service failed the sign in, user profile cannot be loaded’

at the first, the welcoming screen came like usual but it was taking forever. I shut down and started it again a few times then something came like ‘preparing windows’ and  then it brought to me a temporary account. I watched a few working videos and changed my regedit and swapped’.bak’ something like that as the instructions then restarted but doesn’t work. I tried again but now it brings me to the screen that ‘the user profile service failed the sign in, user profile cannot be loaded’. I can’t log into ANY account. I can’t even create a new one. When I press F8, it brings me to a boot settings and says to choose a boot device and gives a few options but I don’t know what to choose. 

please, please help. I’m really anxious and my online schooling starts the next day, I really need help. I’m crying, please..