GA-P55A-UD4 Windows 7 Ultimate x64 hung at "Starting Windows" screen

[mwesten]

Hi guys, I have a problem with Windows and it's quite frustrating. Before I explain what is happening let me give you my system specifications.

CPU: i5 760
Motherboard: Gigabyte GA-P55A-UD4 bios f15
Ram: 2x2GB g-skill 1600-F3-12800cl7d 4gbrm
Disk: Seagate Barracuda 500GB 7200,12
Graphics: Sapphire Radeon HD 6870 1Gb GDDR5
DVD Drive: LG GH22NS50
PSU: corsair tx650w


Ok so I've put in the Windows 7 DVD, booted from it, deleted the partitions and created them anew and formatted the non-system one where Windows is to be installed. Windows then extracts the files normally and reboots the system. Here's where things get tricky. The system hangs after the screen "Setup is updating registry settings" and doesn't move anywhere. I even left it on during the night and it didn't budge. In some instances (I've tried installing more than 10 times) I actually get pass this screen but then get stuck at "Completing installation". And I even got pass that screen in one attempt when I ejected the CD, but when the system rebooted, it hung at "Starting Windows" screen.
Now I have read a lot about this problem on the forums and here's what I've tried so far, to no avail of course:

Removing one stick of ram

Removing all external devices, everything not needed and setting the floppy drive to NONE in BIOS

Removing everything from USB slots and disabling them in BIOS

Switching SATA connectors on the motherboard

Install seven in ahci mode

Install xp

I have tried installing Windows 7 from a dvd as well as from a USB key

Thats about everything I tried with no success.

test ram with memtest..ok

test hd....ok

Does anybody have any idea what could be causing this and what the solution might be? It's a new computer, was built yesterday and it's really frustrating not getting it to work.

Yesterday i've tried installing windows 7 with sp1 integrated in ide mode. Installation ok. I install drivers from Gigabyte's cd, the last amd's drivers for vga, and  last updates from windows updates.
I reboot the system and it hung at "Starting Windows" screen. i've tried start windows in safe mode with no success. i've tried recovery mode with no success.

I suppose there is incompatibilty p55a-ud4 with sapphire hd6870. Have any idea what could be causing this and what the solution might be?

Thank you

some screen of my pc:

these screens appear after  "Starting Windows" screen after windows installation:

[mwesten]

Anybody can help me?

[Dark Mantis]

Hi and welcome to the Gigabyte Forum.

Well considering the tests you have already tried and they seem to have passed I thinkl the next thing tpo check ios the CPU socket for bent pins.

Take all the usual anti-static precautions.

Very carefully remove the heatsink and fan. Probably a slight twisting motion is best to release the two as the thermal paste can act like a glue.

Once off remove the CPU taking extreme care both physically and electrically(static) and place somewhere safe.

Make sure that the lighting is very good and even.

Now scrutinise the socket for any pins that are out of alignment, even slightly.
If in any doubt whatsoever take a couple of macro (close up) photos of the socket and post them on here for us to check.

Also look at the bottom of the CPU at the lands (little copper circles) and make sure that there is a mark in each somewhere near the centre.
If there are any missing marks or any of the pins are obviously bent then that is your problem.

Before refitting the CPU clean off all residue of the old thermal paste and the same on the heatsink and then apply a small amount (about the size of a grain of rice) to the centre of the CPU once it is inserted in the socket.