I installed HP PC Hardware Diagnostics onto my Windows 8.1 x64 laptop HP Envy m6 1104er and used the recommended option "UEFI partition on hard drive".
The tools are now available from the boot menu and they work. But Windows 8.1 does not boot as it says ntoskrnl.exe cannot be found or it is damaged, or it does not have a correct digital signature. I have Windows 8.1 installation media, which I burned using an official image downloaded from microsoft.com. But it does not boot either. It says that it cannot verify a digital signature for acpi.sys.
Please could you help me with solving that. Did the HP software create a new partition? How do I identify and delete one then?
By the way, the laptop has been a disappointment from the very beginning as it has very short battery life of 2 hours, does not recognise bootable media in many cases, does not allow installation of any other system except for Windows 8 (I needed Windows Server 2012, but it would not work with laptop's hardware and HP does not provide compatible drivers), hangs when I connect it to an LCD projector not to mention very weak case which cracked on the first week. I doubt that I will purchase another HP laptop. The Chinese manufacturers are known for their bad quality, but this laptop is the worst I have ever had.