If the laptop is powering on but has a blank screen or simply powering on and off repeatedly without booting, open the panel underneath and reseat the RAM. After, boot your laptop into safe mode with networking, download the bios update from support.hp.com/drivers and install them. Run a Dism /Online /Cleanup-image/RestoreHealth from the command prompt after that. Then run a SFC /scannow and then a chkdsk with the /scan /f /x /r /perf. All these commands need to be run with administrator privileges.