When i move the screen the back light goes off. I don't know how to bring it back up again.

This is often caused by sectors on your hard drive going bad which have critical operating system files on them required for the system to boot up. Another cause is your memory might now be bad. Pay close attention to the text on he blue screen, commonly referred to as the Blue Screen of Death (BSOD). My recommendation is to use a utility from Steve Gibson at Gibson Research, it's very inexpensive and if the hard drive is recoverable, his tool will bring it back to life. If his utility finds a bad sector on the drive, it'll move that data to a good sector and render the system usable again. This utility can take several hours but it's worth the wait. You're only other option is to reinstall the operating system using the F3 option, or as a fresh install but please, please make sure you have your data backed up. If you don't know how to do this then I'd recommend taking it to a service professional, or a friend that knows computers. If the data isn't important, or you know it's backed up then go for it. Here's the link to Gibson's site and the tool is called SpinRite: https://www.grc.com/default.htm. I've been using his tools for over 30 years.

this is a commom issue with windows 8 on HPs. turn off your automatic updates then contact windows. the updates usually gets to 13% and then freezes.

Replace your convergence ic's and bias resistors. Good to go!

Have you any background on electronics? The problem actually could come from a leaky or defective capacitor in the inverter board of your monitor. If you know how to actually open up your monitor the capacitor will look like something 'bloated". But if you don't actually know electronics and don't know how to open up your monitor i would suggest bringing it on an expert rather than you doing it and end up making more problems.
A capacitor should look like this:

a bloated one should have its top side almost like a dome not flat as it usually looks like.

screen is half blank when i bring up book i'm reading

The monitor has failed, it is almost always cheaper to replace it than fix it.

It sounds to me like you either have a bad capacitor on the inverter board(The board that lights up the screen),or a bad bulb in the screen itself.Open the back of the TV,and look at the can shaped items called capacitors on the circuit boards.If any of them have the tops,or bottoms bulged out,they need to be replaced.This should get it working again.I hope this helps.If you have any questions,please let me know.Thank You very much!

Tyler

Remove screensaver and sleep settings. And wait for the same duration. It is goes blank and locks up, report again. Else it is a problem with the screen saver. Change the screensaver and try again

it looks like LCD inverter(fluerasan) broke down.