8 Beep codes indicate LCD failure. I’d suggest that you follow the steps mentioned below and check if the system switches ON.
If the system is not switching ON please connect the external monitor and check if the system is switching ON then I would suggest that you run the diagnostics on the computer by following the steps mentioned below and check if there is any issue with the hardware on your system.
This same thing happened to me. Luckily I just needed to have some visual cord reconnected. Have you tried plugging your computer into another monster to make sure the computer works? I plugged mine into my tv and it worked perfectly fine until I got the visual cord fixed.