# OS-2: Windows Installation, Boot, and Recovery

Status: not started

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:

```powershell
reagentc /info
```

What it does:
- Shows whether Windows Recovery Environment is enabled.
- Useful when checking whether local recovery tools are available.

```powershell
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.

```powershell
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.

```powershell
sfc /scannow
```

What it does:
- Scans protected Windows system files and repairs corrupted files when possible.
- Use for suspected Windows system file corruption.

```powershell
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:

```bash
lsblk
```

What it does:
- Lists block devices such as drives and partitions.
- Useful for understanding disk layout before installation or recovery work.

```bash
df -h
```

What it does:
- Shows mounted file systems and disk usage in human-readable units.

```bash
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?