Do you have a job? Do some overtime and leave the computer alone. With the money you make you can get something better.
I am trying to say that you have is a lemon. It happens. Sorry.
For the amount of work you are doing to fix this, you really need to get some help from others. Once a problem PC or laptop is over two years old, there is not much reasonable hope it will ever be 'good as new'. It may have a bad defect due to manufacturing.
What kind of PC do you really need? Something portable? something you can leave on a desktop?
Tablet devices now a re perhaps the best low-cost way of going mobile. The Amazon fire has what most people need in a portable device. At $99 there is nothing like it. It works. It has clued storage. You can link it to a Bluetooth keyboard.
Or get a used Apple iPad.
Otherwise, you can get a good used desktop for under $99 with a fair warranty.
Don't give up, just dump the lemon.
And I know what you mean. I have had it happen to me.