There's a good reason why LC Power isn't very popular on here: they make EXTREMELY low-quality PSUs (they make PSUs that should be avoided at all costs). I'm sorry to say it, but this PSU is probably the sole reason why this happened. I regret to say that there's a chance that you may have lost your entire computer. This is why it's so extremely important to avoid low-quality PSUs. They can literally be a fire hazard.
It's miraculous that you got 8 years out of it, but that doesn't mean it's any good. Ask any PSU expert what they think of LC Power's PSUs and they will all tell you that they are absolute junk and should be avoided no matter what the cost is. What you experienced today is one of the many reasons why PSUs like these should be avoided.
I will replace PSU in my main computer which is Cooler Master and it's under warranty until September. This Cooler master one will go to this second PC... Which 500-600W PSU would you recommend?