I have P7P55D-E Evo board, Intel i5 655K, Asus EAH5850 DirectCU, and Kingston HyperX 4x2gb 1600Mhz..
Here's the prob..
Firstly I have problem with those memory, but i solve that by taking 2 of the off (let's find aout that later), but now those POST led's blinks few sec and then stop to VGA_led, wich keep light on. Tried also my old 8800GTS, but no good.
Checked all those power connections etc..
You said you replaced EAH5850 with 8800GTS, though for test purposes. Replacing is replacing. The motherboard does not know if the replacement is temporary for test purposes or not.
I try to clear cmos but no good.. Heard about those DRAM inserting problems, i tried several times to put rams on/off, and also tried with one memory stick. Still VGA light stays on, and no POST screen..
Power off the computer with the case power button and power it back on and see if the computer starts now.
I had a similar problem with my P7P55D when I built my rig, though not as severely as yours. Maybe once every ten-to-fifteen cold bootups. I even tried to press the power button for four-five seconds to give full power to my computer, thinking that it might help.
When my computer got stuck at VGA LED, I powered it off and then back on, it worked flawlessly for hours. ( This is why I am suggesting you to power off and back on. )
But one day ( after about six months ) I realized that my computer never gets stuck at VGA LED. I tried to figure out what I might have done in order to eliminate the problem. I did nothing except that I replaced my WD HDD with OCZ SSD and re-installed Windows.
I realize that getting stuck at VGA LED is not related to Windows or to HDD. It is a BIOS enumeration of hardware before POST. But it is gone. Strange.
This could be related to ambient temperature because I built my computer in winter and the annoyance went away at summer time. Now winter is coming back. If it is related to temperatures, I will soon find out.
Further to my post above, I no longer have the cold-boot problem.
The ambient temperatures have dropped to 13-15 deg C but I did not have the getting-stuck-at-VGA-LED condition I mentioned above.
Maybe my problem was not related to the low ambient temperatures.
Maybe the BIOS update I now remember I did to my motherboard in June ( version 1702 which was released early June for P7P55D ) corrected the cold-boot VGA problem for my Sapphire Radeon HD5770. This VGA card was very new when I built my computer. This is an PCIe 2.1 card and the BIOS version was not fully aware of PCIe 2.1 cards.
If I experience the problem again, I will let people know.