But I noticed that by leaving the 20 pin mobo power cable connected & removing the 4pin CPU power cable the case comes to life and all the fans, HDDs & CPU fan work but no screen output. Tried removing the PCI Nvidia card & using the built in video output but the same.
What could possibly be the fault here? Motherboard or CPU?
Whats the effect of connecting/disconnecting the 4pin CPU power cable?
Why is every thing working on removing this cable.
Looks like either the processor or mobo is putting something like a full short across the 12 rails. You could try with the CPU out but 'clicking noise' sounds like an electrical short so a check for mountings that might have nicked a track on the PCB - sometimes the laquer gives a false but temporary sense of security.
If "mobo" the Power button will not turn comp power off if pressed and held in.
Click I would still be thinking of something that moves as it was working. what about ram. if you have two sticks try with one. AS bad ram can corrupt Hard Drive, then it would not be able to read it hence clicking