Thank you Erblemoof, I'm seriously considering doing this now, though it's a bit scary.
I just got this laptop from my employer, and the screen (non-HD, non-touch) is ridiculously bad.
Every degree higher or lower in viewing alters the colors.
Because of this, the top of the screen and the bottom show differently, and to make it all worse, the screen doesn't fold back enough to get the optimal color scheme   ::) 
It's embarrassing really that HP could put this on the market.

This HP 450 G4 is still one of the better budget laptop computers out there when price is compared to performance.
And unless you are a person whose job involves designing or engineering drawing on a day-to-day  basis, you are most likely never going to notice the shortcomings of its display quality. Perfomance-wise, this laptop is top-notch in the endless choice of laptops in the same price range. Of course, its practicality and nice looks doesn't hurt either.

All in all, good PC, but this is the worst touchpad I have ever used.

I want to buy this laptop .. But I'm afraid of the temperature of the body of the laptop as you mentioned .. What do you advise me

It would be nice to see an image of the screen under sunny conditions

I bought this laptop on sale for a great price. Hated the screen. I searched through Notebookcheck for 15.6" laptops with the highest rated displays. The best was the SAMSUNG LTN156HL01 which comes in the MSI PE60-2QEi581. The LTN156HL01 is the same thickness and has the same screw mounting points as the panel in the ProBook 450 G4, so I purchased it and installed it. It works great. My ProBook 450 G4 now has the best laptop display I have ever owned.

Customers certainly should not have to go through these lengths to address issues with laptop computers, but at least it is possible. I'm posting this in case anyone reads this review, so the know the option to upgrade the panel exists.

I agree with Serg - why there is PWM detected here?

In other reviews:
http://laptopmedia.com/review/hp-probook-450-g4-review-intels-new-kaby-lake-cpus-isnt-the-only-improvement/#pwm-screen-flickering

PWM is also missing after 50% brightness and under this point - it is 25.6 KHz, much larger than your measurement.

NotebookCheck, please make a comment for that.

http://www.notebookcheck.net/Acer-Aspire-E5-575G-i5-7200U-GTX-950M-Notebook-Review.178326.0.html
Acer Aspire E5-575G
Display: Chi Mei CMN15C4, TN, 1920x1080, 15.6  - PWM not detected

In this Review: HP ProBook 450 G4 Y8B60EA
Display: Chi Mei CMN15C4, TN, 1920x1080, 15.6  - PWM detected 50 Hz

Who is right?