2.1.2. Perform OS installations and upgrades in a diverse environment. (Obj. 1.2)

💡 First Principle: A clean OS installation provides the most stable environment, but a well-planned upgrade can preserve user data and settings.

As a technician, you will frequently be tasked with installing or upgrading operating systems. There are two primary paths you can take: a clean install or an in-place upgrade. A clean install involves completely wiping the target storage drive (or partition) and installing a fresh, pristine copy of the OS. This is the most reliable method, as it eliminates any pre-existing software conflicts, registry errors, malware, or performance-degrading clutter. It results in the most stable and performant system possible. An in-place upgrade, on the other hand, installs the new OS version directly over the old one, attempting to migrate all user files, settings, and applications. While far more convenient for the user, this method carries the risk of bringing old problems into the new environment.

The installation itself can be initiated from various boot methods. The most common today is using a bootable USB drive, created with tools like the Windows Media Creation Tool or Rufus. In corporate environments, network installation via PXE (Preboot eXecution Environment) is common. This allows a computer to boot from its network card and pull the OS installation files from a central server, enabling rapid deployment to many machines at once. Many computers also ship with a hidden recovery partition on the hard drive, which contains a factory image of the OS that can be used to restore the system to its original state.

When deciding on a method, partitioning the disk is a key consideration. The disk is divided into logical sections called partitions. The two main partitioning schemes are MBR (Master Boot Record), an older standard limited to four primary partitions and disks up to 2TB, and GPT (GUID Partition Table), the modern standard required for UEFI-based systems. GPT overcomes MBR's limitations, supporting over 128 partitions and disks much larger than 2TB. For any modern installation, GPT is the preferred choice.

Technician's Action Plan: Scenario: A user's computer running Windows 10 is eligible for an in-place upgrade to Windows 11. They want to proceed but are worried about losing their years of family photos and documents. What is your process?

1. Prioritize Data Integrity: Explain to the user that while in-place upgrades are designed to preserve data, things can go wrong. State that the absolute most critical first step is to perform a full backup of their data.
2. Perform the Backup: Guide the user in backing up all their critical files (Documents, Desktop, Pictures, etc.) to an external hard drive or a cloud storage service like OneDrive. Verify that the backup is complete and the files are accessible from the backup location. This is your safety net.
3. Check System Compatibility: Before starting the upgrade, run the PC Health Check app from Microsoft. This will confirm the system meets all Windows 11 requirements, most notably the TPM (Trusted Platform Module) 2.0 and Secure Boot capabilities, which are mandatory security features.
4. Initiate the Upgrade: Once backed up and compatibility is confirmed, you can start the in-place upgrade using Windows Update or the Windows 11 Installation Assistant.
5. Post-Upgrade Verification: After the upgrade completes, verify that all user data is intact, key applications are functioning correctly, and devices like the printer and webcam are working. If there are major issues, your backup ensures you can perform a clean install of Windows 11 and restore the user's data without any loss.

Key Trade-Off: Convenience (Upgrade) vs. Stability (Clean Install). An in-place upgrade saves the user the hassle of reinstalling applications and reconfiguring settings. A clean install takes more time upfront but provides a "like-new" system free from the baggage of the old OS, often resulting in better performance and fewer mysterious issues down the line. For a critical system or one that is already experiencing problems, a clean install is always the superior professional choice.

Reflection Question: Why is performing a full data backup the most critical step before any OS installation or upgrade, regardless of the method chosen?