For many people, Windows seems to slow down over time. Quite a few people fix this by regularly reinstalling Windows. But do you need to reinstall Windows regularly? And, if so, how often do you need to reinstall it?

Reinstalling Windows is inconvenient. You have to back up all your data, go through the install process, reinstall all your favorite programs, and restore your data. All these activities suck up valuable time.

Why Windows Slows Down Over Time

The main reason people reinstall Windows is that it slows down over time. But why do Windows systems slow down over time?

  • Startup Programs: Examine a Windows system that’s slowed down and you’ll likely to find many additional startup programs have been installed, lengthening the boot process, cluttering the system tray with useless icons, and consuming CPU, memory, and other system resources in the background. Worse yet, some computers may come with a considerable amount of unnecessary startup programs out of the box thanks to manufacturer-installed bloatware.
  • Explorer Plug-ins, Services, and More: Applications that add shortcuts to Windows Explorer’s context menu can make right-clicking on files take much longer if they’re poorly programmed. Other programs may install themselves as a system service, so they’re running in the background even though you can’t see them. Even if they aren’t in the system tray, useless programs can slow down your PC.
  • Heavy Security Suites: Security suites like Norton are often very heavy, consuming a lot of resources to perform all their functions. You don’t need a full security suite—just an antivirus program.
  • PC Cleaning Tools: PC cleaning tools are generally scams. Paradoxically, they can make your computer even slower if they add themselves as a startup program and run in the background. The scammiest PC cleaning programs may also install additional spyware and other junk. You can use something like CCleaner instead, but there are even better options.
  • Other Junk: Poorly written applications may clutter your system with useless DLL files and fill your registry with unnecessary entries. The worst applications may not clean up properly after themselves, leaving this stuff on your system even after you uninstall them.
  • Browser Toolbars: Legitimate browser extensions can slow down your browser enough, but junk add-ons like the terrible Ask.com toolbar can slow things down even more.

In other words, the leading cause of a Windows system slowing down over time is installing junk software.

How To Prevent Windows From Slowing Down Over Time

To keep your Windows system running like new, you need to take proper care of it.

  • Install only software you’ll use. Choose well-written, lightweight programs that respect your system instead of slowing it down.
  • Pay attention when installing software and avoid installing browser toolbars, spyware, and other garbage software that can slow down your computer.
  • Regularly uninstall software you don’t use from the Control Panel. Even useful software may run in the background and slow things down.
  • Occasionally use tools like Disk Cleanup to remove the temporary files wasting space on your hard drive. You don’t have to reinstall Windows to get rid of these.
  • Take proper care of your web browser, too. Use a minimal selection of browser extensions. If you don’t use a browser extension, uninstall it — it’s just taking up system resources and slowing your browser down for no good reason.
  • Carefully select lightweight, minimal security programs. All you need to install on Windows now is an antivirus app and possibly an anti-exploit app. With Windows 10, the built-in Windows Defender plus an anti-exploit app like Malwarebytes make a great combination.
  • Use a startup manager tool like the one built into Windows 10 to prune useless programs from your startup process.

Tips for Testing Software

If you want to test software without letting it mess up your system, consider installing it in a virtual machine or using a sandboxing tool like Sandboxie to isolate it from the rest of your system. The software won’t be able to mess with your primary operating system—just your virtual machine or sandbox environment.

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So When Do I Need to Reinstall Windows?

If you’re taking proper care of Windows, you shouldn’t need to reinstall it regularly. There’s one exception, however: You should reinstall Windows when upgrading to a new version of Windows. Skip the upgrade install and go straight for a clean install, which will work better. Performing an upgrade install can result in a variety of issues—it’s better to start with a clean slate.

If your Windows system has slowed down and isn’t speeding up no matter how many programs you uninstall, you should consider reinstalling Windows. Reinstalling Windows may often be a faster way to get rid of malware and fix other system issues than actually troubleshooting and repairing the specific problem. However, you should try to take better care of Windows in the future.

If your Windows computer is running fine, you don’t need to spend hours reinstalling your operating system—even if it’s been years since you last reinstalled Windows. That’s a sign you’re doing an excellent job of taking care of your Windows system.

How To Quickly Reinstall Windows

If you are going to reinstall Windows, Windows 10 makes this much more manageable. Windows 10’s “Refresh Your PC” feature effectively performs a quick reinstall of Windows, removing all your installed desktop programs and any other system modifications, while preserving your personal files. You don’t even need a Windows disc to do this.

If you’re using a previous version of Windows, you can reinstall Windows from a Windows installation disc or restore it from your computer’s recovery partition. Before you reinstall Windows from the disc or recovery partition, make sure you have backups of all your important files. Read our guide to reinstalling Windows for more information.


There are other reasons to reinstall Windows. Maybe you like that clean, “like new” Windows environment. However, if you carefully select the software you install and take proper care of your Windows system, you shouldn’t have to reinstall Windows regularly.

Sure, file system fragmentation can cause Windows to slow down over time as well—but Windows automatically defragments your hard drive and defragmentation isn’t even necessary on SSDs.

Chris Hoffman Chris Hoffman
Chris Hoffman is Editor in Chief of How-To Geek. He's written about technology for nearly a decade and was a PCWorld columnist for two years. Since 2011, Chris has written over 2,000 articles that have been read more than 500 million times---and that's just here at How-To Geek.
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