HP DC7900 sff won't power up

[stafel]

Good day, my HP DC7900 sff won't power up all of a sudden. When I press the power button nothing ever comes up, not even the fans. However, there is a small light blinking in the middle of the mobo and it is accompanied by a faint sound. The faint sound, it sounds like a feedback coming from headphones/headsets or speakers when you plug them or switch them on.

And seconds later after attempting to power it up, the automatic voltage regulator makes the same sound a minute after you turn it on (can't describe it, but it sounds like a soft, metallic/electric clicking sound that you can likely hear from most electric devices when you switch them on).

I'd also like to add that I can hear soft, faint electric sounds behind the PC then the voltage regulator makes a clicking sound after a couple of minutes after powering it on before this, but the PC doesn't turn off and anything goes normally, well, for almost three years.

 

[googlyeyedchicken]

It might be your power supply has gone bad. I would also try using another power cable, resetting the CMOS, checking if the fans are stuck, removing dust from your PC, and testing your power supply.

 

[stafel]

Well, this is kinda embarrassing but the dust may be the answer. The whole rig has some small webs in it. Still I can't find a way to clean the PSU's insides since I can't find gas dusters in here for some reason. Might have to buy overseas online. As for the fans, it has been pretty noisy lately, but I can't determine if it's the front or the PSU's. Though I would bet on the front one since when I put my ear closer to the rig. But I've been pretty concerned with the PSU thanks to all those noises from back then even when the PC's still clean and now.

How do I reset the CMOS?

 

[Calvin7]

HP 460974-001 Power Supply
https://www.amazon.com/HP-460974-001-Power-Supply-462435-001/dp/B00HMJSZ4K

 

[stafel]

I have a question, what are the odds of the other parts and components getting fried by the faulty PSU?