Power on Clicking/Flashing not booting

I came home yesterday to my desktop making a clicking sound and the lights flashing in sequence with the clicking. I'm guessing it is the power supply but any ideas would be helpful. i unplugged everything and tried again, it still clicks - almost like it is misfiring. I dont hear any fans come on but didnt listen closely for that ( i will ). the sound seems to be coming from the top of the tower - where the power supply is. im wondering if this is a bad connection or i just need a new power supply. the unit is about 3 years old, i dont always turn it off but generally keep it maintained quite well. i dont do any downloading and have a good antivirus in the case that it may be virus related…? it would be nice to be able to save the cash of taking it in for repair. the monitors are not the issue as well, i tested that angle and its not a fuse. any help is appreciated

Open up the side of the tower case before powering-up. Do you see the red RAM pre-warm indicator light turned on, (even before powering up) ? Machines draw a "trickle" from the PSU even when turned off, in order to keep the RAM pre-warmed. The red or orange light indicates this is functioning, and only goes off if the main power cord is unplugged from the machine. If it is on, you know that at least the 5 amp leg of the PSU is trickling. _________________________________- Then power-up momentarily to determine if the fans come alive and blow vigorously. If not, turn off the machine "immediately". Were you able to determine during the above test, whether the "clicking" sound was originating at or near the PSU? IF not, might it have been "clicking" from one of your Hard Drives? You may have a failed PSU or a failed Hard Drive. If you have a competent PSU tester (not just a multi-meter) pull the connectors to test the PSU. If not, and you still suspect the PSU, only way to determine is to replace it. (some shops will accept return of a recently purchased PSU if not needed. ask first) If the "clicking" was from the Hard Drive (or not from the fans or PSU) then consider swapping in a substitute Hard Drive. Sure you won't have Windows installed, but should get to a nag screen saying No Operating System found. But then if you were getting no Display whatsoever, "not even POST test information, then the graphics card may be what was causing the "clicking" Check the graphics card for leaking/bulging capacitors and for mechanical failure of any heatsink fan attached to the graphics card. Keep us posted.

Doug, Thanks very much for your quick and very detailed reply. Ok, without going to the step of swaping out any of the hard drives, i did the other tests. I took off the cover. I did not see any light in or around the RAM - however, im not familiar with where it should be so i may not have been looking in the right spot. I dusted further - which I have learned from this process that I should do more oftern - it was like a pharohs tomb in there. I then attempted the power on: It was still clicking (and it happens right away upon pressing the power button), The fan on the mother board did start up, The clicking sound is definitely coming from the power supply, However, the lights for the hard drives which are on the opposite corner from power supply, were still flashing to correspond with the clicking. I did check the graphics card but did not notice any buldging or leaking - yet, the same applies - I may just not know the right place/way to look. So, I think Ive ruled out the graphics card and im thinking it is indeed the power supply - but im not able to rule out the possible issue with the hard drive. I will update with progress. Thanks again