Acer Aspire One - 5520 Boot Problem

Hello,

I originally had a serious MBR (Master Boot Record) virus on the laptop, and decided to make a backup of necessary data then do a factory restore using the ALT-F10 option during boot.

The Acer restore program started and I choose factory restore. Everything completed OK.

The laptop rebooted, and now says "Operating System not found".

Again, there were no errors during the factory restore, the progress indicators for the restore completed without any issue.

The laptop does not have a CD drive, so I created a bootable USB drive to boot the system to run utilities on the drive.
It will not boot from the USB drive either.

The USB stick is bootable, because I was able to boot it in another computer, and it comes up fine.

I checked the BIOS and it does recognize the hard drive and the USB stick that is connected.
I set the boot order to boot the USB stick first, then the hard drive. During the boot process it ends up again with "Operating System not found".

During boot I can press F12 and in the boot list that comes up both the hard drive and USB show.
If I select any of them, the system does not boot the OS.

Any help or guidance would be appreciated.
Thanks.