How to Speed Up a Slow Windows 10 または 11 パーソナルコンピュータ (Desktop or Laptop)

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If your Windows 10 または 11 computer feels sluggish, this simple step-by-step guide will help you clean up, repair, and optimize performance safely. Always create a System Restore Point before making any major system changes.

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1️⃣ Enable System Restore

Before doing anything else, turn on System Protection so you can easily roll back if something goes wrong.

  1. 押す 勝つ + S and type “System Restore”
  2. クリック Create a restore point
  3. Click the System drive (通常は、C:) under Protection Settings
  4. クリック Configure
  5. 確保 “Turn on system protection” is selected
  6. Under Disk Space Usage, allocate 3% Max Usage
  7. クリック Apply → OK

Create a restore point manually:

  1. クリック Create…
  2. Type a name you’ll remember, e.g. “My Restore – 4th April 2022”
  3. クリック Create

Tip: Avoid skipping this step — it can save your system if something breaks later.

2️⃣ Remove Unwanted Startup Programs

There are several places where startup programs hide. Check them all and disable what you don’t need.

Current user startup

shell:startup

All users startup

shell:common startup

Registry entries

Always back up your registry before making changes!

  1. Open ラン (勝つ + R) → type regedit
  2. バックアップ: File → Export
  3. Check the following locations:

Current User

Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

Local Machine

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

Delete any unwanted startup items.

Task Manager

  1. 押す Ctrlキー + シフト + Esc
  2. Go to the Startup tab
  3. Disable unnecessary items

Task Scheduler

  1. 押す 勝つ + S, タイプ Task Scheduler
  2. Review scheduled tasks and disable ones you don’t need starting automatically.

Be careful not to disable security, GPU, or system driver entries.

3️⃣ Remove Unused Software, アプリ, and Bloatware

使用 IOBit Uninstaller (Free version is good enough for this guide). It automatically creates a System Restore Point before uninstalling.

Avoid clicking “Install recommended extras” during setup — uncheck those boxes.

I once removed an important driver accidentally — System Restore saved me. Always create a restore point first.

4️⃣ Clean Up Disk Space and Fix Windows Errors

IOLO System Mechanic is one of the best all-in-one tools for cleaning up disk space, repairing registry issues, and boosting overall Windows performance. It automatically detects system clutter, broken shortcuts, and startup delays — all with one click.

💰 Limited-time offer: 取得する 50% off System Mechanic here through our partner link.

代わりに, you can manually clean using:

  • ディスククリーンアップ (cleanmgr)
  • Storage Sense (Settings → System → Storage)

These help remove temp files, ログファイル, and Windows Update leftovers.

5️⃣ Repair Windows Errors with Built-in Tools

DISM (Deployment Image Servicing and Management)

Fixes corrupted Windows system files. Open コマンド・プロンプト (管理者) または ターミナル (管理者) and run:

DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth

Internet connection required for /RestoreHealth.

SFC (System File Checker)

Checks and restores system files:

sfc /scannow

CHKDSK (Check Disk)

Fix file system errors. For a full scan:

chkdsk /r /x

This requires a reboot and can take several hours — save your work first.

For a quicker scan (no bad sector recovery):

chkdsk /x

6️⃣ Check Windows Log Files for Critical Errors

  1. 押す 勝つ + X → Select Event Viewer
  2. Expand Windows Logs → Application
  3. クリック Filter Current Log…
  4. Tick Critical と エラー
  5. クリック OK
  6. Search Google for the Event ID and message to find fixes
  7. Repeat the same steps under Windows Logs → System

例: “Disk 7 – The device has a bad block” often means a failing drive.

✅ Quick Summary

Step アクション
1 Create a System Restore Point
2 Disable unwanted startup programs
3 Uninstall unused software & apps
4 Clean up disk space and fix errors
5 Run DISM, SFC, and CHKDSK commands
6 Check Event Viewer for recurring errors

Recommended Tools

Tool Purpose Notes
IOBit Uninstaller Remove programs safely Free version is fine
IOLO System Mechanic System optimization Optional, paid
CCleaner Disk cleanup Use carefully; avoid registry cleaning
Autoruns (Microsoft Sysinternals) Deep startup control Advanced users only

Disclaimer

This guide is for educational purposes. Always back up your data and create a restore point before modifying system files or the registry.

Disclosure: Some links may be affiliate links. If you buy through them, I may earn a small commission at no extra cost to you.