The problem relates to something call UEFI. When you switch a computer on you usually see a bit of writing or maybe the manufacturers logo for a few seconds before Windows starts to load. These messages are generated by something called the BIOS, effectively a program that "describes" the basic computer hardware to the operating system (this is a simplified explanation). The concept of the BIOS dates back over 30 years to the earliest PCs and hence is rather long in the tooth -- clearly computers have changed dramatically in that time. UEFI (Unified Extensible Firmware Interface) is the modern replacement and UEFI is installed on just about all new computers.
UEFI is intended to speed up the startup process, but more importantly is designed to give something called a secure boot. There are viruses around called rootkits that can hijack the operating system before it even starts; UEFI gets around this through the concept of a signed or authorised operating system -- one which fails the signature test will simply not load. This has considerable benefits (some would say) for Microsoft, as it makes it harder for people to run operating systems other than Windows on computers and allows them to control piracy by linking the copy of Windows 8 to the physical computer on which it is installed (as if anyone would bother pirating Windows 8!). It's also of benefit to the security services as they can 'knock out' specific computers.
At this stage, although most new computers come with Windows 8 pre-installed, most existing computers in the world run previous versions of Windows that pre-date all of this. As these have to be accommodated, it is necessary to turn off the security features to allow so-called "legacy" operating systems to install and operate. This is done through a BIOS (UEFI) setting and can be invoked by pressing a certain key when switching on the computer, typically F2, F10 or the Delete key depending on the manufacturer. Changing the security options may also be useful when trying to resolve Windows 8 startup problems.
And herein lies the problem. On many of the laptops from the Acer group (Acer, Packard Bell, Gateway, emachines) you don't appear to be able to change the security settings. So, when things go wrong you are effectively stuck. And things "going wrong" is not necessarily down to viruses or people doing the wrong thing -- in many of the reported cases this happens after Windows itself has installed updates. Although Acer is one of the world's largest computer manufacturers and a highly respected brand, prospective purchases might want to consider these matters whilst a widely publicised solution to the problem remains unavailable.