Windows 8 won't boot - SSDs Gigabyte mobos AHCI UEFI

(edit: This is becoming my most accessed page - so don't forget to complain to Gigabyte because they've obviously done something wrong - if they don't know they can't fix it)

Well I just been in a week of hell as my new computer will only boot on the 5th attempt or so. It was fine at first. I have a Gigabyte GA-Z77-D3H motherboard, an OCZ Vertex Plus SSD and a Segate 2T HD.

This all started after I installed the F18 version of the bios, I can't remember which version was on there originally. After that on most attempts to boot I would get 'data can not be read from disk'. Also the SSD (which contains the operating system) would disappear from the boot list in the bios. I think changing the cooler was a coincidence to throw me off the track.

The following worked for me, it may or may not do the same for you so do some research.

I did some research and it seemed I should turn on AHCI (whatever) in Peripherals in the Bios (Sata Mode selection) and that would make good. Well windows did boot and then crashed. One time then I did this and set it back to IDE Windows said I had to use a restore point to get it going.

So further reading and apparently its not straight forward enabling AHCI after you've installed windows 8. There is a link here but the info is wrong in the main article and only corrected in the comments so I thought I would put the correct solution here.

This uses Regedit and you can completely destroy your system with regedit so use with care and I take no responsibility for any damage trying to do the following might cause. Also you need to have installed the Motherboard disk controller drivers.

amended from their website

• Exit all applications
• Go to the start screen and type in regedit.
• If you see the UAC (User Account Control) dialogue box, just click continue
• Locate the the following registry subkey:
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\StartOverride
  In the right pane, you will find a key labelled O with the value '3'. Double click on this and set the value to '0'
   
• Go up one level to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\
  there should be a key called ErrorControl which has a value '3'. set this to '0'
  
• Reboot your machine and set Peripherals / Sata mode selection / to 'AHCI'. 
• Save and exit and all should be good.

I shall be monitoring my system. Hope this post cuts down the time it takes you to solve this problem.