Why is your operating system not found?

You recently upgraded the memory in your desktop computer by adding a new memory module for a total of 2GB of RAM. When you power on the computer, the correct amount of memory displays in the BIOS POST, but instead of a Windows the message “Operating System not found” is displayed. What is the most likely reason for this error?

A) The new memory modules are faulty

B) The hard drive was damaged during the memory installation

C) The power supply is faulty

D) A hard drive cable was dislodged during the memory installation