Hello,
Windows Defender is the built‑in antivirus program included with Windows, and it is enabled by default.
If you disable Windows Defender, your PC will no longer be protected from threats, so if you temporarily turn it off for any reason, it is recommended to enable it again afterward.
When you install a compatible third‑party antivirus program (non‑Microsoft), Windows Defender will automatically be disabled.
However, this can sometimes lead to issues such as failed Windows Updates, network problems, or other unexpected troubles.
In addition, using a paid third‑party antivirus program may be unnecessary, since Windows Defender is available for free and provides sufficient protection for most users.
Modern Windows 11 PCs are powerful enough that background scans performed by Windows Defender should not cause noticeable performance issues.
Windows also includes Microsoft Edge, a built‑in browser that works together with Windows Defender.
However, you can use third‑party browsers as well, such as Google Chrome or Firefox.
Each browser uses a different search engine, so installing multiple browsers and switching between them is also an option.
If you prefer Microsoft Edge, you can change its default search engine:
Settings > Privacy, Search, and Services > Search and service settings > Address bar and search > Search engine
From there, you can choose your preferred search engine.
Please note that system applications built into Windows such as Microsoft Edge and Windows Security are essential components of the operating system and cannot be removed.