My screen is black when the laptop is on

The first step for fixing a black screen is performing a hard reset. To do this, hold the power button down for a few seconds until your TouchSmart turns off. After a few seconds, hold the power button again to turn your device back on. If the black screen isn’t gone after the reset, the display screen may be faulty/broken. The only way to fix this is to replace the screen entirely.

If you have any further questions, here is a link to the troubleshooting guide for your device: HP TouchSmart 15-r015dx Troubleshooting