Lastly, if Windows 8 detects any boot problem with the system, it will automatically load up Windows RE boot options. If your board supports the new UEFI firmware, this will happen automatically. If not, you would still need to press the F8 key, but you will not have a lot of time since Windows 8 loads so much faster.
Instead, the best way would be to use Methods 1 or 2. However, if you can’t boot into Windows 8 at all and the boot options don’t come up automatically, you’ll have to hope you created a Windows 8 USB Recovery Drive. A recovery drive in Windows 8 will basically let you create a bootable USB flash drive that will load the Windows RE environment in case it won’t load automatically and you can’t get into Windows.
I will cover how to create a recovery drive on a USB flash drive tomorrow, so come back soon to read that article! Enjoy!
"Method 3 – Automatic or Recovery Drive --Windows 8 System Recovery Options"
Reference : online-tech-tips.com