I'm trying to fix an older computer that all of a sudden decided not to boot up. Here's the deal: I turn it on, the power-on LED lights up, fans power-up, but that's it. Also, a constant clicking noise is coming from somewhere, but I have no idea where. My initial thought was the HDD, but it still clicks when I disconnect or replace it. Then I thought maybe the CD drives, but they also aren't the problem. After searching online, I was led to the PSU, but after replacing that I get the same problem. I also thought maybe the cpu fan was the cause of the clicking, but I briefly powered-up w/o the fan connected and it still clicked. I was finding some mention of beep codes online, but this is more of a click than that annoying, loud beep. I've never heard a beep out of this computer though, mainly b/c it's not mine. I don't see a speaker in it though...
Also, I've troubleshooted as much as possible. Reseated all connectors, no burn marks anywhere, etc. I'm at a loss. Any ideas? Thanks,