Z400 freezes while booting or won't boot at all

[jponnio]

Okay, here's my full story as copied from my post on reddit.com/r/techsupport.

My computer is a HP Z400 Workstation.

• Windows 7 pro / 64-bit
• Intel Xeon Processor W3550 3.06 GHz Quad Core
• nVidia Quadro 600 1GB
• Chipset Intel® X58 Express
• 6gb PC3-10600 DDR3-1333 ECC Unbuffered DIMM
• 475W PSU by DELTA
  
• 2x 250GB Seagate HDDs @7200rmp, Integrated RAID

My problem is that the setup is freezing (seemingly) randomly. It first started about a month ago. I cleaned it inside and relocated the unit for better airflow. It worked fine until now. No BSOD or any other error messages. Everything just freezes and I have to do a hard reset. Now it keeps freezing even faster from startup than before. Here's what I know:

• CPU temperatures are about 45C when idle
• GPU temp is 50C when idle. I ran MSI Kombustor stress test and it climbed to 68C and it froze.
• I have cleaned all the dust from every fan and heat sink.
• I have made a fresh OS install.

• I have installed the latest drivers for the Quadro 600 manually. EDIT: After this I had about 40mins uptime which I used trying to get memtest86 to work via bootable USB. Then a BSOD occurred for the first time. Pictures here.
  

• I can't get the memtest86 to work via USB. It seems like my BIOS doesn't fully support this. There is a BIOS update available which would make USB boot work with FAT12 but I have no idea if that's the issue. I did install my Win 7 with bootable USB and I tested the USB stick with my laptop (and it runs the memtest just fine). I don't feel safe flashing my BIOS due to random freezes.

• I have made absolutely no changes in my setup.

Please help. I am amazed that I have been able to make this post without freezes to cut me off.

EDIT 2 Freezed in a safe mode, too. Rebooted in safe mode again, tried to change the screen resolution and got messed up like this.  After a reboot in normal mode, my desktop still looked like that. Another reboot, it looked normal.

EDIT 3 Tried switching the Quadro to different PCI-e slot. Didn't help.

EDIT 4 Tried another graphics card (GeForce GTX 460). Once I booted, computer did chkdsk automatically and rebooted. Windows started with 640x480 resolution and after a while rebooted itself without warning. It told me to choose between safe modes and normal startup and froze there.

EDIT 5 Trying the RAM sticks separately now. First two made no change, still froze. Now I'm on the third and the system won't even boot. Feels like every day the system works less and freezes earlier on.

EDIT 6 Just tried to boot with another HDD with both original HDDs disconnected. No help. It freezes on the BIOS load up screen or won't boot at all. I switched everything back to original parts except the GTX 460 and it won't boot. I put the Quadro 600 back in and it booted to the BIOS load up screen and froze.

EDIT 7 I got the system to boot by clearing CMOS. I proceeded to Windows Repair and it froze on the Startup Repair screen. Getting really frustrated.

So.. now I'm at the point where I can not boot my system at all. I tried already disconnecting everything (incl. RAM and CPU fan) from the mobo except CPU and removing the CMOS battery for 5mins to see if I can get the two beeps and two reds, but I only got the pre-video memory error with five beeps. I added the RAMs and got six beeps. 

Now I am able to boot (although I'm told that my system has no BIOS installed and need to boot with F1) to the point where I choose Windows Repair or normal startup. Win Repair freezes and now I've stared at the Starting Windows screen with the Windows logo pulsing.

[MSLEEE]

When I see what you have done, it looks like there is a faulty hardware such as the system board or CPU. This may be  related to the thermal.

[JeppyG]

I am sorry that you have been experiencing the computer equivalent of Clue (R) by Milton Bradley.  That is a very frustrating experience.

I agree with JohnL. 

In my experience, this sort of behavior usually indicates one of the following:

 - a bad RAM DIMM

 - a bad graphics card

 - a bad motherboard

 - a bad CPU

The graphics card almost always results in BIOS beeps and your switching effectively removed it from consideration.  Bad RAM can cause similar problems but the problem usually moves with the specific DIMM, and the memtest will almost always catch it.  

That leaves the MB and CPU as likely candidates.

[jponnio]

Thank you for your response.

I found out that my unit has some kind of "business class" warranty for 3 years and it ends 3/24/2014, I didn't know that because I got this unit off of my local equivalent for craigslist.

I called the HP support and based on our conversation the tech thinks it's a faulty HDD(s) or system board. They're sending a tech for on-site repairs tomorrow. I got lucky!

I will post again when the guy is done with my unit and inform what the problem was and if this is considered solved.

[jponnio]

The tech guy came today and changed my system board while I were at work. I got home and turned to unit on, let it be idle about 30 mins and started browsing the internet normally. After about another 30 mins it shut down itself without shutting Windows down and booted itself.

It did not succeed and told me the usual message "Windows failed to start" and I chose the "Windows repair".

It loaded the Windows files and switched off again fans blazing full speed. Now it's on a constant loop of "Windows failed to start" -> "Windows repair" -> Boot ->  "Windows failed to start"  etc... without touching the thing.

It won't boot from my bootable Win 7 USB key. I tried disconnecting both HDDs and connected a laptop's HDD which has Win 7 Home Premium 64, result was otherwise similar with the exception of a flash of a blue screen.

I connected the HDD back to the laptop and it ran the Windows repair for 15 minutes and now it's working fine (thank god).

It's Friday evening here where I'm typing from so I have to wait until Monday to contact the tech support again.

So this remains unsolved. I have no idea what could be causing this and the tech was very confident that it's the sysbo's fault.