Cannot adjust brightness

Say, "Go to settings," or swipe down from the top of the screen and select Settings. Select Display. Adjust brightness using the slider. You can also toggle Adaptive Brightness on or off.

Adjust the Screen Brightness on Your Echo Show - Amazon.com

Suggest you download and install an app. The one I use is "sky at dawn" from com.teragon.skyatdawnlw.lite

go to start-->control panel--->display--->adjust brightness

i need to know what operating system you use this will work for only Vista and 7 and 8 and 8.1

Try this:
https://forums.lenovo.com/t5/Lenovo-P-Y-and-Z-series/Z400-Adjusting-the-Brightness-in-Windows-8-1/ta-p/1303113

take a flashlight shine it at the screen at an angle and you should barely make out whats their, go through the settings menu and adjust.

what not book?, 1984 to now. vast types. made. by HP
what OS. what operating systems.
chrome, the browser chrome?
sounds to me like hardware failure. but .... little to go on , here.

it is still on warranty... check on service ... or you can try to download drivers .. or new chipset for your laptop..
or on startup hit f and chose last known good configuration thaht worked.

You can adjust the brightness or color of the LCD display as needed. 1. Set the POWER switch to CAMERA position. (In the PLAYER mode, you may only setup the LCD while the tape is playing.) 2. Open the LCD screen, and the LCD switches on. 3. Press the MENU button. 4. Turn the MENU DIAL so that VIEWER is highlighted and then press the ENTER button. 5. Turn the MENU DIAL so that LCD ADJUST is highlighted. 6. Press the ENTER button to enter the sub-menu. 7. Turn the MENU DIAL so that it highlights the menu item you want to adjust (BRIGHT SELECT, BRIGHT ADJUST, COLOR ADJUST). 8. Press the ENTER button again. You may select NORMAL or SUPER in the BRIGHT SELECT feature and press the ENTER button to save the setting. Use the MENU DIAL to adjust the value of BRIGHT ADJUST and COLOR ADJUST. You can set values for BRIGHT ADJUST between 00 ~ 35 and COLOR ADJUST between 00 ~ 35. 9. Press the MENU button to finish the setting.