RAM wasn't installed properly
I took out my RAM and reinstalled it to see if it had dust and i didnt click it in propey and my PC would turn off in 4 seconds when i opened it and restart so i waited for 12 hours and tried again and it was powering up but there was no HDMI signal so them i opened up again to see motherboard and fixed the unclicked ram and so is the RAM damaged?
Did you check there were no obstructions in the RAM slots before you re-seated them? I've rectified several build issues by removing and blowing out RAM slots in the past - it seems they're particularly sensitive to any dirt or debris getting in there (I even had a PC fail to post because an eyelash blocked a pin on an old laptop), and a poor connection can give you all sorts of weird & wacky errors.
Something like a DSLR dust blower is ideal for this.