Acer Aspire one restoring problem

Hello,
I recently tried to restore my acer aspire one netbook to factory settings, but I accidentally turned it off. When I started it up again it said could not start because of missing hardware, or softwar. I told me I needed to put the disk in but i do not have a cd drive,on my acer nor do I have a usb one. How do i get it to run again? Answers needed urgently