I have a 21.5 iMac that initially would not boot up. I kept getting the boot up progress line but then it would start over and sometimes it would boot but then crash in the middle of surfing or doing anything. Now it will not boot up at all. I can see 4 green light on the motherboard and hear the drive running (slight whisper sound) but it will not boot up. When I took the screen off I did damage the LVDS cable and purchased another one (Willhom LVDS LCD Display eDP Embedded Display Port Cable (60/60-Pin) 923-01669 Replacement for iMac Retina 4K 21.5 inch A1418 (Mid 2017) A2116 (Early 2019) off Amazon and installed it. Any idea what to look for next? I'm thinking maybe a new hard drive?