Computer sometimes does not start without me flipping the PSU switch on and off (multiple times)

[Jeppesu]

Hello, so recently I've started experiencing a problem with my computer.
Rarely when I press the power up button it will boot up just fine like a computer should do, but in most cases I have to flip the power supply switch on and off (often more than 1 time) for the computer to boot. However when it does boot up, everything works perfectly.

I don't know what to make of this, is it the sign of a failing power supply or does it have something to do with my motherboard? I have checked that every cable is plugged in fine.
I also read about a paperclip test for power supplies, which I intend to try. I have not been able to perform the test yet since I could not find a paperclip.
Here's the test: Youtube link

Here are my computer specs
Intel core i5 2500k @ 4,5 GHz | Corsair Hydro H70 | Geforce Gtx 680 2GB | Msi Z77 MPOWER | Corsair Vengeance 16GB 1600 MHz | OCZ Vector 256Gb | OCZ Agility 3 120GB | WD Caviar Blue 1TB | Corsair AX 650W 80+ Gold | SilverStone Raven RV02-E

I've owned the motherboard and power supply for ~2 years, every component was purchased new.

 

[Outlander_04]

Possibly a psu problem
possibly a mb issue
possibly a front panel connector issue

First thing is to disconnect the front panel switches and see if the computer will boot by shorting the power switch pins momentarily with a screw driver .
If it does start then the case is the issue

If it doesnt try updating the BIOS to the latest version
If that doesnt fix it then

try a new psu

 

[Jeppesu]

Possibly a psu problem
possibly a mb issue
possibly a front panel connector issue

First thing is to disconnect the front panel switches and see if the computer will boot by shorting the power switch pins momentarily with a screw driver .
If it does start then the case is the issue

If it doesnt try updating the BIOS to the latest version
If that doesnt fix it then

try a new psu

If this is the case, how does that explain why the computer will start by flipping the power supply switch?

 

[Outlander_04]

The first two are less likely than the third option
but its free to try them so you might as well before you spend money on a new psu

 

[Jeppesu]

The first two are less likely than the third option
but its free to try them so you might as well before you spend money on a new psu

Ah yes, will do.
Thank you for the tips!