On which two occasions is it most likely that a technician will have to perform a clean operating system installation if a backup has not been performed? (Choose two.)

A clean installation of an operating system is usually required when:

1. The existing operating system is corrupted: If the operating system has been damaged to the point where it cannot be repaired through other means (such as system repair, restoration, or in-place upgrades), a clean install is often the best or only option to get the system back to a functioning state.
2. A new replacement hard drive is installed in a computer: If the computer’s primary hard drive, which contains the operating system, fails or is replaced, a clean installation of the operating system will be necessary, as the new drive will not have an operating system on it.

The other scenarios listed do not typically require a clean operating system installation:

• A user requires access to a new printer: This situation usually requires the installation of the appropriate printer drivers and software, not a reinstallation of the entire operating system.
• The existing security software requires upgrading: Upgrading security software is a common maintenance task and does not require reinstalling the operating system. It can typically be done within the existing environment.
• The computer is being moved to a different network: Moving a computer to a different network does not affect the installed operating system.