PC Power supply problem

Hello,

I'm new to this site, and I signed up because I think the community in this site can help me. I'm experiencing a problem probably about the power supply of my PC. When I start the PC, it does not boot up, power led indicator does not flash, hard drive is silent, and the only thing that I can notice is the processor fan. My video card fan will start if I initially spin the fan.


I saw many possible answers in this site and tried the following :

1) Holding the power switch by 30 seconds (All components unplugged including power cable)
2) Cleaning fan dust.
3) Removing ram cards and video cards.
4) Power up without processor fan running
5) Plugging power cable to different outlet ( same voltage of course)
6) Trying different power cables
7) Leaving PC for 24-48 hours to drain power from capacitors of power supply then trying after waiting.

None of these worked for me. Are there any solution to this before I buy another power supply?

I am borrowing a PSU (Same wattage and specifications) from my friend and I am going to check if the PSU is really the problem.

Additional info :
My Power Supply has no switch by itself, it can be switched on only through the PC power switch.