Question Power Supply Autopsy

[Lautermilch]

I have a ASUS ATX with a WD 3GB and a WD SSD. No overclocking or that kindof thing.
Two years with 450watt PS and due to indoor temp I turned the PC off during the day.
So I come in a few days ago I power it up and it runs fine but a lot of fan noise and I smell the burning eletrical scent.
I power down and find the bottom air filter under the PS is totally blocked. When I pulled the cord out of the PS I see it is melted and one of the prongs is missing. Thank God no fire occured.
So I get a new Thermaltake 700 watt and pc is all well.
My question is could the dust have done that or was it the PS going bad?

 

[Dark Lord of Tech]

Dust probably contributed to the end of the power supply. Keep an eye on the Thermaltake , they are poor power supplies.

 

[delaro]

Combination of a bad PSU and poor ground at your outlet or even the polarity swapped.

 

[Ralston18]

Dust or going bad - could either or both.

But with a blocked air filter - likely that the heat build up caused the PSU to fail versus some failure due to long term and overloaded or even normal use within the PSU's rated wattage.