What were you running when this system crashed like this?
This sounds very odd that you had scrolling columns with numbers.
If nothing is displayed including the HP logo not displayed at boot:
If your system has a video card added and integrated video as an option, remove the video card and connect to the integrated video instead. If problem solved then its either bad video card or power supply is weak. If problem remains or you do not have a video card to remove then continue to nect steps.
I'd remove and reseat the memory sticks with the computer off and then try to boot. If still a black screen shut down and then if you have more than 1 memory stick installed, remove all but 1 stick and try to boot. If still a black screen shut it down again and try to boot with the other spare stick.
Last effort is if a spare power supply is available to swap out with this system.
* Your hard drive may still be good with a computer that is dead. You can always buy a new computer and buy an external hard drive enclosure and install the hard drive from this system into the enclosure and be able to access your data on the new computer. Sometimes you need to take ownership of files and folders though depending on how you had your system configured.
