Malware (Omniboxes) found in my platforms: IE, Chrome and Firefox

On 22 Nov 2015, I've reported to Norton about a Malware (Omniboxes) embedded into all my search engines. My PC is installed with Norton Internet Security but is unable to detect or remove this. A Norton Technician named Jessie Paraz eventually got me to use Norton Power Eraser to remove it. Outcome was, my PC unable to connect with internet and Omniboxes still exist. Seek help from other Norton technicians but no avail. I've formatted my PC and reinstalled the system files and realised Omniboxes still found in my search engines. Anyone here could help me?