Please help me to install Ubuntu 13.04 in a dual boot setup with Windows 8 on my Sony Vaio E Series SVE14125CNB laptop. When I try to install Ubuntu, after the installation is finished, the system gives me a message that says: operating system missing. Then I changed the BIOS setting as normal, and it only boots Windows 8.
I also have SVE14125CNB laptop and I installed Ubutnu 13.04 (dual boot with Windows 8) by following instructions given in this link Installing on a Pre-Installed Windows 8 System (UEFI Supported)
How did you install Ubuntu in first place and what BIOS settings did you change? May be you will have to fix grub. Read about it here boot-repair