I have read your post and understand that you need assistance in fixing the no power issue. I will definitely help you.
I request you to perform the steps from the link below and check if that solves the issue.
If the LED is on solid, the power supply is probably good and the problem is most likely caused by a defective component (processor, memory, PCI card) or a defective motherboard. Have the computer serviced, or remove the components and replace them, one at a time, to find and replace the defective component.
Hope this answers your query. Let me know for more.