loading issue

Please help me

I followed all the video tutorials on YouTube

everything was working for me

the computer was on for several days

after turning off the laptop for the second time, the site won't start

the page loads very slowly

and eventually it doesn't load at all

once it seemed to load but without a menu it said there were problems with the database

I uploaded and installed a new database in the folders

it works, the test in Denver passes

Denver itself is working! The test passes adequately!

What should I do? I need to learn

we have a website on Drupal in our company and I need to somehow manage

to fill it and change it, for this I created a mockup at home

but it won't start, what should I do?

Help me

inmeda@mail.ru Sergey