I just performed a fresh installation of ubuntu 13.04 on a machine that previously had a working installation. I had mangled part of my previous installation in an attmpt to setup a new GTX Titan graphics card and decided I was better off restarting from scratch.
During the installation, I selected the option to completely erase the existing contents of my primary disk and create a fresh installation of ubuntu (I do have a second disk that I plan not to erase). The installation appears to complete successfully, but when I boot the machine it fails (takes me to a grub rescue prompt).
I booted with a LiveCD and ran boot-repair (output at http://paste.ubuntu.com/5889178/). It claims to have repaired my grub installation but I still just get the grub rescue prompt when I try to boot the machine.