operating system not found after updates
Hi, My computer is a Lenovo x120e AMD 64. I have been running Ubuntu 12.04 LTS since April with no significant problems. Today, I installed recommended security updates which is something I do regularly. The system required restart to complete the updates and so I restarted the computer. Upon restart, I now get the error message "Operating System not found". I switched the bios to diagnostic mode and I see where the computer is finding my hard drive, "Fixed Disk: WDC etc." Prior to this problem, my hard disk was operating normally with no loud noises or other indications of a problem.
Unfortunately, I no longer have a good usb start up disk and this computer does not have a CD drive. I do have another computer running 12.04 but I have not installed the most recent updates on that one and it works fine. I do not, however, have a fast enough internet connection to download another copy of the operating system.
Am I the only one having this problem? What should I do next?