I just bought an asus notebook. It had no OS-s installed so I did the following to it. I installed win8 in uefi mode. I then added ubuntu to the mix. I installed it in uefi mode too using the guide at: http://www.linuxbsdos.com/2012/11/05/dual-boot-windows-8-and-ubuntu-12-10-on-uefi-hardware/
I have gone as far as running boot-repair on my installed ubuntu, and have not used the EasyBCD part. I can now dual-boot ubuntu and win8 with no problems using GRUB2.
My question is the following: if I want to remove the dual-boot setup and install just ubuntu, can I use the ubuntu liveCD and choose the erase disk option? I know this will remove all my data, but that is allright. My fear is ending up with an unbootable machine. Can that happen?