How can I rebuild windows 8 on Lenovo Ideapad yoga 11S?

I managed to get a virus (System Healer) on my Lenovo Ideapad Yoga 11S, tried to delete it from task manager/programs, but browsers still didn`t worked safely. Took the notebook to a service where they`ve opened it apparently to identify if the virus has attacked the hardware as well. Brought it back home, and tried to bring t back to factory settings, but half way through I got a warning, the system could not reboot properly as the operation system may been damaged.

Could you please advise how can I reload/ install Windows 8 on my Lenovo Ideapad Yoga 11S