The print keeps giving me an error message saying it can't read my memory card.

The screen won’t change, no matter what external buttons are pressed.

The flash is turned on but the flash itself won’t open.

External button for zoom isn’t responding. The camera won’t zoom in or out.

Make sure the printer is plugged in if it still won’t turn on replace the ac adapter.

The printer is most likely out of ink, so replace the ink cartridges

If the battery is fully charged and the camera won’t turn on then the motherboard may need to be replaced. Sony Cyber-shot DSC-HX300 Motherboard Replacement

While the camera is powered on and the lens cap is removed, if there is no obvious damage or obstruction that would prevent the LCD screen from functioning properly, try pressing the LCD/Finder button located near the ON/OFF button. If the screen is still failing to power on then the battery may need charging or the screen may need to be replaced. Sony Cyber-shot DSC-HX300 LCD Screen Replacement

While the camera is on try unplugging and plugging the HDMI cable back into the port, if the computer still doesn’t identify the camera then the HDMI port may need to be replaced. Sony Cyber-shot DSC-HX300 HDMI/USB port Replacement