I was normally using my laptop, closed the lid normally and when I returned to use it I opened the lid half of the screen went white and the other half was multi- colored stripes, then it just went completely white, turned off the laptop and turned it back on and this time the screen was just completely black.
What happened to my hp pavilion dv5 laptop?
And how can this be fixed?

It might be a the flat cable of the display that got disconnected or broke, it might also be the screen itself which has failed> If it's possible, open the laptop and chech if the cable is still intact, if it is, the problem is most likely the screen itself. If that's the case, it might just be better to buy a new laptop, there is no problem with the HDD so you can still save all your data.

Based on personal experience, HP laptops tend to overheat. I have had my HP G42 laptop repaired twice in a span of 2 years. First time was because the system fan broke after numerous times of shutting down due to overheating. The second one was about a month ago when I had the same issue that you are having right now. The screen just went black with the power still on. At first I suspected it to be similar to the first problem until I had a technician look at it. I was told that the GPU chip needs to be replaced as it was "almost" fried due to the overheating issues. The part would cost me almost US$200 so I said screw it. He did offer me an alternative to simply repairing it for only a quarter of the cost but did not guarantee that it will last a long time. I simple took the cheap route and is still using my laptop until now error free so far. I also run Core Temp so I can monitor the laptop's running temperature limiting it to the basic programs I need to use. Nothing graphic intensive as I have learned that it is what primarily triggers an overheating problem.

Cutting the long story short, have the GPU chip checked as it is most likely to be the culprit of the problem.

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