BIOSTAR TZ77B motherboard making clicking sound

[ajmcguire]

I built a new computer in May and it has been working great. But today when I booted it up it, it seemed to boot slower than normal and now there is a a clicking noise coming from the motherboard. I'm not positive it's coming from the motherboard itself, but thats what it sounds like -- and I've ruled out most everything else. The click happens about once every 3 seconds.

Here is what I've tried:
1. disconnected power from all HDs and rebooted, same noise
2. disconnected cpu heatsink fan, same noise
3. disconnected gpu, same noise
4. stopped all other system fans, same noise

system details:
BIOSTAR TZ77B motherboard
i5-2400 sandy bridge 3.1ghz
Seasonic M12II 620W PSU
Radeon HD 6950 2GB GPU
Intel 330 SSD
a couple other regular HDs

Any other suggestions or ideas?

 

[utahraptor]

I have thought on this long and hard. The only idea I have is that the fan in the power supply is going out or something is in it getting hit by the blades.