I am having a little trouble following where you are exactly, and the mention of C: leads me to believe you already have some type of install on the drive.
A system with a UEFI bios can install Windows 8 as either MBR or UEFI. For the Boot drive, an MBR install requires a MBR configured drive and a UEFI install requires a GPT configured drive, which you probably already know. This means the entire hard drive, not just certain partitions.
If you start with a clean drive, no partitions and the drive considered basically RAW, booting into the UEFI install will convert the drive to GPT then create 3 partitions. The OS will be installed in the space after those 3 partitions. You boot into a UEFI install by using a Boot Device menu and select the UEFI version of the install media. It works this way in most bioses, but some may be set to boot to UEFI only, in which case you need to change the option to install a MBR configuration.
You should also note some install media have problems with UEFI. The DVD made from an .iso file created with the Windows 8 download will not boot into UEFI. The flash drive works on both versions. The Official DVD from Microsoft will boot UEFI, as it should.
How you boot your system after the install is for UEFI, boot the Windows Boot Manger. For an MBR install, you boot the drive.
Hopefully this will help you, but if your situation is not resolved, be a little more specific about where you are and where you need to be in your install.