Well, the UEFI add more options to the sometimes confusing and in itself, wide variety of options we had with BIOS, and many computers yet remain the old BIOS as your new Dell. From what I've read about dual boot where can coexist peacefully windows and linux on the same hard disk as before, in the days of UEFI is not as simple as before, especially if the version of Windows with which it has to coexist Fedora is windows 8.

The problem is that windows 8 is nothing hospitable, do not like to be friendly with other operating systems and often the same manufacturers, Dell in this case, the hardware lock from the UEFI to prevent someone from modifying the operating system that comes factory . Of course this is not the case since you've been able to install Fedora on your pc.

I know this is not about Fedora, but read it, but it could help you clear your doubts: http://askubuntu.com/questions/221835/installing-ubuntu-on-a-pre-installed-windows-8-64-bit-system-uefi-supported

Good Luck