Potential power supply failure

Morning all, I just wanted to run something by the Dell community. A colleagues Dell computer has failed. I had a look at it and am somewhat confused by it. The power button is blinking orange/amber, which suggests to me that there is a power problem. However, when I tested the power supply using the inbuilt system, the power seemed to be operating fine with the green light on the back showing throughout. Unfortunately I don't have another psu to plug in. I've tested the hard drive separately and that is completely fine, nothing wrong there.

Any thoughts? Is it a busted power supply or is something else going on?