Need Help with Asus P5K-E: problem on first start-up

Since a couple of days I have a very weird problem with the following config:
Asus P5K-E/WIFI-AP
Corsair TWIN2X2048-6400, 2x1GB, DDR2-800
Intel Core 2 Duo E6750, Dual Core, 2.66 GHz
Asus EN8600GT SILENT/2DHT/256M
Corsair CMPSU-520HXEU, 520W
Samsung SP2504C, P120S, 7200rpm

At the very first "morning" startup, the pc does not want to boot, the hdd led does not show up.
No display.
Reset an retry will not help.

However, if I switch off manually the Power Supply, wait a little, re-start then it boots complaining about "overclocking failed".
I enter the boot setup, do no modification, save and exit, no problem at all!

ps: when it manages to boot, i observe that it does it in 2 times: I see my akasa fan controller showing up, then suddenly off during one second and eventually starts up. I don't remember such a behavior before.

Is this possible there's a defect on the MB?
Many thanx and sorry for my so-called english.

CPU-Z 1.41 report file
Processor(s)
Number of processors 1
Number of cores 2 per processor
Number of threads 2 (max 2) per processor
Name Intel Core 2 Duo E6750
Code Name Conroe
Specification Intel(R) Core(TM)2 Duo CPU E6750 @ 2.66GHz
Package Socket 775 LGA
Family/Model/Stepping 6.F.B
Extended Family/Model 6.F
Core Stepping G0
Technology 65 nm
Core Speed 3199.7 MHz
Multiplier x Bus speed 8.0 x 400.0 MHz
Rated Bus speed 1599.9 MHz
Stock frequency 2666 MHz
Instruction sets MMX, SSE, SSE2, SSE3, SSSE3, EM64T
L1 Data cache (per processor) 2 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache (per processor) 2 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache (per processor) 4096 KBytes, 16-way set associative, 64-byte line size
Chipset & Memory
Northbridge Intel P35/G33/G31 rev. A2
Southbridge Intel 82801IR (ICH9R) rev. 02
Graphic Interface PCI-Express
PCI-E Link Width x16
PCI-E Max Link Width x16
Memory Type DDR2
Memory Size 2048 MBytes
Memory Frequency 400.0 MHz (1:1)
CAS# Latency (tCL) 5.0 clocks
RAS# to CAS# (tRCD) 5 clocks
RAS# Precharge (tRP) 5 clocks
Cycle Time (tRAS) 15 clocks
Command Rate (CR) 2T
System
System Manufacturer System manufacturer
System Name P5K-E
System S/N System Serial Number
Mainboard Vendor ASUSTeK Computer INC.
Mainboard Model P5K-E
BIOS Vendor American Megatrends Inc.
BIOS Version 0806
BIOS Date 10/31/2007
Memory SPD
Module 1 DDR2, PC2-6400 (400 MHz), 1024 MBytes, Corsair
Module 2 DDR2, PC2-6400 (400 MHz), 1024 MBytes, Corsair
Software
Windows Version Microsoft Windows Vista (6.0) Business Edition (Build 6000)
DirectX Version 10.0

yes indeed, i did a last update of my bios (0806).
i wonder whether it can be a problem with the core voltage@3200 or something like that...

and what i do not get is the strange startup in 2 steps.

, too, have had a similar problems involving an ASUS P5K-E motherboard, since its purchase. The system will not automatically recover from sleep states, whether S1 or S3. I also cannot reliably get an automatic reboot when I perform a Shutdown/Restart of the system. I first thought this is because I have Windows XP 64 bit installed. I have tried a myriad of bios settings, and I have tried several measure measures of troubleshooting that could be linked to XP 65 bit/Visa, but to no avail. When the problem happens, the only way I can recover the system is to completely power down the system from the wall plug. I have talked to ASUS technical staff twice about this issue, and they seem oblivious. What should I do?

This is strange, I have this exact motherboard and I've had no problems at all whatsoever! It's running good guns. These are my specs...

CPU Intel Core 2 Duo E6850 (3.0Ghz/Conroe/4MB/1333FSB/EMT64/XD/Dual Core)
Motherboard Asus P5K-E-WIFI S775, QuadCore, P35, FSB1333, 2xPCIEx16, RAID, 1394a, GbLAN, ATX
Memory Geil GX22GB6400UDC 2GB Kit (2x1GB) PC2-6400 800mhz DDR2 Ultra, 4-4-4-12
Video Card Gigabyte GV-NX88S320H-B-RH Geforce 8800GTS, 320MB, PCI Express, Dual Dual Link DVI, HDTV, TV OUT
Hard Disk Western Digital WD7500AAKS 750gb 7200rpm 16mb SATAII/300, NCQ
Optical Drive Optional Pioneer Nero Burning Software
Optical Drive #2 Pioneer DVR-212BK 8x/18x Dual/Single Unbranded Black OEM - SATA
Floppy Drive Panasonic JU-257A-727P 1.44mb Black Floppy Drive
Case Antec "Nine Hundred" Tower Gaming Case with Side Window - Black, NO PSU, 9 Drive Bays, Top mounted 200mm exhaust fan, Top USB/IEEE1394/Audio
Power Supply OCZ OCZ1010GXSSLI GAMEXSTREAM 1010W SLI READY PSU
System Assembly Full Parts Assembly and Testing for 13 and above components without software installation
Cooler #1 Antec 120mm Smart Cool (Thermally controlled Clear fan)

It is a custom system, not off the shelf and it was purchased in early December of 2007. Since then I've added...

2x Western Digital WD5000AAKS 500gb 7200rpm 16mb SATAII/300, NCQ
1x Western Digital WD10EACS Caviar GreenPower 1TB 7200rpm 16mb SATAII/300, NCQ

I haven't messed with any of the bios settings or tried overclocking this computer or anything. Everything was left stock standard out of their boxes and to be honest, this system has been rock bloody solid for me. No problems, no glitches, and certainly no problems at all from the motherboard. Is it a slightly different model to yours? Or did I get lucky and buy one of the non lemons?
Also this computer has run Vista Premium its whole life and to be honest I use this computer heaps and taxed it a lot. Never a problem, I'm surprised to have stumbled across this thread. Is there something else I need to worry about with this motherboard? Possible problems in the future to prepare for?

I3loodTeeth

I had a similar issue with a P5N-D running my E6320 when oveclocked.
It wouldn't cold boot at the overclocked setting, however once it had been on for a few seconds initially, I could re-set it and it would then boot ok at the desired overclocked speed.
I upped the voltage on the N/B to 1.4v and this seemed to cure the problem.