I have Windows 8.1 Pro with all automatic updates successfully installed, running on:

Sabertooth Z77 motherboard

GEForce GTX 770 video

Intel i7-3770K LGA1155

Xonar DSX PCIE 7.1 audio card

Corsair TX850 power

16GB of Corsair Vengeance DDR3 DRAM

More than adequate cooling.

The machine has never been right from first build. It just doesn't boot reliably, often requiring 20+ minutes of reboot attempts, resets and random fiddling before it eventually starts. At first I thought the problem was Windows 8 famously not shutting down properly. Certainly, Windows 8.1 has improved things. But it just won't boot properly and I'm at a loss what to do.

Here's what typically happens, but it's different every time and things are not necessarily in the below order:

1. POST always succeeds with no issues.

2. Windows 8 logo appears with circle of dots.

3. Screen goes black for a few minutes. HDD LED flashes like its life depends on flashing.

4. Monitor gets fed up and powers down.

5. HDD gets tired and has a break.

6. Monitor springs back to life, but only to show a black screen for a minute or two.

7. Windows 8 logo re-appears with circle of dots.

8. Screen goes black again.

9. HDD decides to have another go and flash like it's flashing in the Olympics.

10. (Not always!) Windows announces there is a problem booting (you don't say) and offers some help but:

a) The fix option refuses to accept the install DVD saying it's not valid

b) Enabling boot logging produces a 12KB log file full of space. Just space space space and no words or numbers at all.

11. Rebooting or resetting generally reproduces steps 1-10.

12. Just occasionally, I get a login screen, hence here I am posting this using the problem machine. When it boots, everything seems to work fine. No obvious issues with any hardware. Device Manager happily reports that all is well, except the SATA AHCI controller didn't start - well, obviously it did start, or something to replace it did, or I wouldn't be here typing this - and neither did the "Multimedia Audio Controller" - although again, something else must be driving the audio because it's working fine.

I did get a WHEA_UNCORRECTABLE_ERROR on screen during boot at one point (only once!), but I don't know how to get at the details and Googling it suggests I need to be a hardware vendor to get the explanation. 

Er, now what? Anyone? Please?

 

What about starting windows in safe mode or last know good config?

The only problem with 'last known good' is there's never been a good. Safe mode produces the same or similar results.Sometimes it'll start, but usually not.

Almost the same system as me except my MB is little better. Issue is most likely your bois settings. Boot from none uefi.

Disable all drives that you don't need to boot your system or choose none uefi , there will be options for this. Disable virtua, if you have it.  Make sure your bios settings is achi format. If you setup windows in some other format like IDE SATA you will have to most likely reinstall the os using achi format. If that is the case you will need to switch back to IDE sata in your bios.

Start with disabling all drives you don't need to boot from. That is including your CDrom

Edit: make sure your bios is up to date

• Edited by colakid 7 hours 29 minutes ago

That's interesting, as I'd already noticed that the problem is worse (100% fail rate, I think) when there is a CD in the drive during boot. Strangely it also seems worse when the PC is cold. (You can see why I'm baffled by it...)

I'll post back after I've tried your suggestions and booted plenty often. Going to take a few days minimum. Thanks.

 

Don't say we are getting the cold boot problem again. That goes back since 2000/98 second.