CX430 (EU) Has developed boot problems

Hi All,



Had a rig running for just over 2yrs now on a CX430 but in the last two months its started causing me real grief.



1. Minor: Coil while got a little worse. Its fine until it idles then it wines for second, quiet for a second, whines for a second again. Consistent pattern. Not a big worry, but maybe related.



2. Serious: Booting

Turned on - Reboot - Fine.

Turned on - Shut down - Start back up(be it a minute or a day later) -Fine.

Turned on - Shut down - Remove AC Supply(230V) - Reconnect AC- Wont Post. Leave AC off for several hours then reconnect, press power and there we go, she boots.



I've checked:

CMOS Battery

Bios Reset

Different GPU

Different RAM

Different DIMM Slots

Clearing board power



When its up and running its perfectly stable, can run furmark or prime95 or both and it wont hiccup. Its just when the AC is off for a minute for any reason(usually me needing to clean/cable tidy something). My electrical knowledge wouldnt be terrible but I cant tell what this is. Some online advice suggested an overcharged cap might do it, but I dont know if that holds water. It makes sense though that a slow dissipation restores operation.



Specs:

Asus P5E3 Workstation

Q6600

2x4GB DDR3 Dimms

HD5770

CX430

Samsung 1TB disk and 830 128GB SSD

Bitfenix outlaw



Right now I'm leaving it sit for another few hours so I can successfully boot it.



Any suggestions as to other steps I could take? Right now I'm looking at verifying the source by using a known good PSU then having to RMA the unit.



Regards,

ED E