comptia-a-plus-core2/notes/OS-2-windows-installation-recovery.md

OS-2: Windows Installation, Boot, and Recovery

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Domain:

• 1.0 Operating Systems

What You Need To Know

Windows installation questions usually test which method fits the situation.

Core install types:

• Clean install: wipes or replaces the existing OS. Best when starting fresh or when the old OS is badly damaged.
• Upgrade install: keeps compatible apps, files, and settings while moving to a newer Windows version.
• Repair install / in-place repair: reinstalls Windows system files while trying to keep user data and applications.
• Image deployment: applies a prepared OS image to one or many computers. Common in business environments.
• Network boot / PXE: boots a computer from the network to install or deploy an OS.

Boot and recovery questions usually test the first tool to try.

Common recovery tools:

• Windows RE: Windows Recovery Environment. This is the recovery menu used for repair options.
• Startup Repair: use when Windows will not boot correctly.
• System Restore: rolls system files/settings back to a restore point. It does not restore personal files.
• Uninstall updates: useful after a bad Windows update breaks startup.
• Reset this PC: reinstalls Windows and can keep or remove user files, depending on the option selected.
• System image recovery: restores the computer from a full system image backup.

Memory Tricks

Install choices:

• Clean = clear the old system.
• Upgrade = up but keep stuff.
• Image = identical installs.
• PXE = Preboot eXecution Environment = boot before local OS.

Recovery choices:

• Startup Repair starts the system again.
• System Restore restores settings, not documents.
• Image Recovery returns the whole picture.
• Reset is the bigger hammer when repair tools fail.

Commands To Enter

Enter these on Windows PowerShell or Command Prompt:

reagentc /info

What it does:

• Shows whether Windows Recovery Environment is enabled.
• Useful when checking whether local recovery tools are available.

shutdown /r /o /t 0

What it does:

• Restarts Windows directly into Advanced Startup options.
• /r means restart.
• /o means go to advanced boot options.
• /t 0 means wait zero seconds.

bcdedit

What it does:

• Displays Boot Configuration Data.
• Useful for viewing boot loader entries.
• Be careful: changing BCD settings can break boot if done incorrectly.

sfc /scannow

What it does:

• Scans protected Windows system files and repairs corrupted files when possible.
• Use for suspected Windows system file corruption.

DISM /Online /Cleanup-Image /RestoreHealth

What it does:

• Repairs the Windows component store used by SFC.
• If SFC cannot repair corruption, DISM is often used before running SFC again.

Enter these on Linux for comparison practice:

lsblk

What it does:

• Lists block devices such as drives and partitions.
• Useful for understanding disk layout before installation or recovery work.

df -h

What it does:

• Shows mounted file systems and disk usage in human-readable units.

sudo reboot

What it does:

• Restarts the Linux system.
• sudo runs the command with administrative privileges.

Mini Lab

Goal:

• Recognize recovery options and practice safe information-gathering commands.

Windows:

1. Run reagentc /info.
2. Record whether Windows RE is enabled.
3. Run sfc /scannow.
4. Record whether Windows found integrity violations.
5. Optional: run DISM /Online /Cleanup-Image /RestoreHealth.
6. Do not change bcdedit settings. Only run bcdedit to view current boot entries.

Linux:

1. Run lsblk.
2. Identify the main disk.
3. Run df -h.
4. Identify the root filesystem and free space.

Quick Check Before Quiz

You are ready for the OS-2 quiz when you can answer these without looking:

• What install type wipes the old OS?
• What install type keeps compatible files/apps/settings?
• Which recovery tool fixes common boot problems?
• What does System Restore affect?
• What command restarts Windows into Advanced Startup?