The trick is the "paper clip trick", I would imagine?? If your new PSU doesn't kick on you case fans when connected with the "paper clip trick", I would say that PSU might be DOA.
If it works to turn on the lights, it is more likely a motherboard issue that took out your PSU in the first place (IMO). I had it happen to me before using a Tagan PSU. My MSI board died, took the PSU & CPU with it. I thought it was the PSU, installed a new one with no luck... Fans but no picture (Dead CPU / MOBO).