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Guide

Fixing and speeding up a Windows PC

Windows errors with real fixes, plus the settings that make an older machine usable again — error 651, Defender, Exe files opening in Notepad, and the Store failing to load.

12 articles · updated August 23, 2026

Most Windows problems announce themselves with an error code and no explanation. The guides below start from the message you are looking at, say what actually causes it, and work through the fixes in the order most likely to solve it.

01

Error messages, and what to do about them

Each of these has a specific cause. The guides work through them in order rather than listing every possible fix.

  1. Front of a server rack with labeled blade servers and bundles of blue and white network cablesError 651 — Connection Failed6 min read
  2. Close-up of a laptop screen showing a web analytics dashboard with a line graph and pie chart0x80072EFD — the Store cannot connect5 min read
  3. Overhead view of a wooden desk crowded with a laptop, newspaper, calculator, coffee, tax forms, and a phoneWindows cannot find — make sure you typed the name correctlyUsually a shortcut or a startup entry pointing at something that has moved.2 min read
  4. Yale padlock and keys resting beside an open printed document and a pen on a wooden deskUnable to turn on Windows Defender5 min read
  5. Hands tap a tablet showing a grid of product thumbnails, an open laptop behind on a wooden tableUnable to select Windows 10 Pro4 min read
  6. Overhead flat lay of a silver laptop, black notebook, pen, potted plant, and a hand holding coffeeExe files opening in Notepad4 min read
02

Making the machine behave

  1. Open laptop in a dark room, screen and backlit keyboard glowing in rainbow colorsSpeeding up a slow computer5 min read
  2. Bearded man in a gray hoodie taps a white tablet held sideways beside a cup of black coffeeAuto-rotate stuck or missing6 min read
  3. Woman in glasses bites a yellow pencil and grins at an open laptop beside a cup of colored pencilsLocking the PC automatically when you walk away5 min read
03

Setting it up the way you want

  1. Apple desktop display showing a green mountain landscape wallpaper on a wooden desk with keyboard and mouseChanging how the desktop looksThe most detailed walkthrough here, with a screenshot for each step.11 min read
  2. Black handheld microphone on a stand in sharp focus, more mics blurred behind under warm stage lightsSetting up speech recognition10 min read
  3. Man in a blue shirt writing on a small notepad beside an open silver laptopFree apps worth installing first6 min read