Computer Power Supplies are not working anymore

So a little back-story. So I have two computers which I built. About a month ago or so one of them just stopped working (no power). This one in particular has a cosair 750w power supply (probably at least 3-4yrs old). So anyways I figured it had just went bad because we hardly ever shut the computer down.

Now last night I took my other computer (corsair 600w power supply) and moved it to the same location as the computer that died. I plugged it in and nothing. So I then checked the outlet. There is definitely power there. I also tried other outlets, still nothing.

SOME OTHER DETAILS:

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1. The first computer has been working for 3+ yrs with no problems.


2. The second computer I built about 2 months ago.


3. The night before the first computer stopped working my wife and I smelt something that smelt like burnt rubber.
   We thought it was coming outside, but I have reason to believe it may have been the power strip. The reason I think it was the power strip is because the second computer made no smell before it died.

PROBLEM / QUESTION:

So with that in mind I am assuming I have a bad power strip. But what I don't understand is how a faulty power strip could cause two power supplies to go bad. Would a power supply go bad because of a lack of power? Or too much power?

PC1 Power Supply - http://www.microcenter.com/product/406089/CX_Series_CX750M_750_Watt_ATX_Modular_Power_Supply

PC2 Power Supply - http://www.microcenter.com/product/406088/CX_Series_CX600M_600_Watt_ATX_Modular_Power_Supply

Answer

Well I did a paper clip test on the power supplies and both actually still work. Its very odd that both would stop working after plugging them into the same outlet. But long story short I spent the night dissecting one of my PC's and found out that the circuit board connected to the power button doesn't work. So now I have to start it with a paper clip until I either fix the switch or get a new case.

Thanks to everyone for sharing your advice.