PC switches on for a few seconds, then goes off - 1 time a day

[SupaMonkey]

Hey guys,
So I built a new PC - works perfectly - save for this little issue.
First time I switch it on each day, it goes on - then off. Then I switch it on again and it works fine for the rest of the day. Even if I switch it on and off various times during that day - it works perfectly - its only the FIRST time of each day that I seem to have to 'switch it on twice'.

What gives?

Thanks in advance!

 

[banthracis]

List full system specs and go through the troubleshooting checklist in my Sig.

Common causes are wiring/bad PSU wiring issues and BIOS issues.
One known cause is certain mobo features like "health check" which cause issues unless diasbled or BIOS updated.

 

[SupaMonkey]

I updated BIOS to latest version
I switched off 'health check' features and 'automatic fan control'
All wiring is fine.
PSU is fine.

Specs:
Intel® Core™ i5 2500 - 3.30GHz Quad Core, Socket 1155, 6MB L3, DMI Bus, 32nm, x64, Intel VT, Intel HD Graphics @ 850MHz, 3 Year
GIGABYTE® P67A-UD3 Mobo
Leadtek GeForce GT430
1x 4GB Transcend Ram Module
GIGABYTE® X9 ATX Chassis - Black - Side Vented Panel - 4x 5.25" & 6x 3.5" Bays - Tool Free Design - 1x 120mm Fan - No PSU
GIGABYTE® ODIN 585W 24-Pin Power Supply, 4 Molex & 5 SATA Power Connectors, Intel LGA775 Ready & Approved, Includes Power Cable
SAMSUNG® B2430H LCD - 24" Wide, 16:9 HD Format, 1920x1080, 5ms Response, 70000:1 Contrast Ratio, 300cd/m² Brightness - D-SUB, DVI, HDMI
Seagate® Barracuda™ 7200.12 Series - 500GB Serial ATA III (SATA3) Plus - Serial ATA 600 (6Gbps) With 16MB Cache @ 7200RPM - NCQ

Ive been building PC's for the last 15years - havent had this issue before...
Its a real bastard to debug because it only happens once a day, so you never know if the issue has resolved until the following day!

 

[banthracis]

We get this issue every once in a while here. Usually turns out to be one of the above. Let us know if problem still persists.