How to speed up a slow computer: a 15-minute checklist for Windows 11

The 15-minute checklist

Save your work before you start: the first step restarts the PC, and the last one may too. The clock is a budget for one pass, not a measurement; a very slow PC takes longer to restart, and that is fine.

Restart the PC, and choose Restart rather than Shut down

Close your apps, then select Start > Power > Restart. When Windows is back, open only the apps you need, which is Microsoft's own advice for a PC that has slowed down with many apps and tabs open.

On Windows 11 the two buttons do different things. Fast Startup is the default when you ask Windows to shut down: it signs you out and closes your apps, but writes the contents of the kernel to the disk instead of discarding them. At the next power-on, Windows loads that saved image from the hibernation file, Hiberfil.sys, including the kernel-mode drivers that were loaded, rather than building the kernel from scratch. That is why a shut-down PC starts quickly, and also why shutting down does not give Windows the clean start a restart does: the kernel and drivers you get back are the ones that were already running. A restart is different: Microsoft's documentation says a full shutdown happens when a restart is requested, so Windows starts clean.

You do not need to turn Fast Startup off; it is what makes a cold start quick. Use Restart when the goal is a clean slate, and make it a habit: Microsoft suggests you reboot at least once a week, which also lets updates install regularly.

Install pending updates

Windows updates often include fixes and performance improvements, so start them early and let them download while you work through the rest.

1. Select Start > Settings > Windows Update > Check for updates.
2. If updates are listed, select Download & install, then carry on with the checklist while they download.
3. Open Advanced options > Optional updates. Microsoft notes that a new non-critical driver listed there may help; select it and Download & install.
4. If Windows asks for a restart, restart to apply the updates, but leave it until the end of this checklist.

Check which version the updates bring, too. As of September 2026, Microsoft's release information lists October 13, 2026 as the end of updates for Windows 11 version 24H2 on Home and Pro editions, while version 25H2 is supported until October 12, 2027. If Windows Update offers version 25H2, install it when you can leave the PC to restart. A PC still on Windows 10 is a different case: its free security updates ended on October 14, 2025, and updating your computer or phone covers what to do about that.

Turn off startup apps you do not need

Apps that start by themselves at sign-in slow the start and then keep running in the background. Task Manager shows which ones cost the most:

1. Press Ctrl + Shift + Esc to open Task Manager.
2. Select Startup apps.
3. Read the Startup impact column, then right-click each app you do not need the moment you sign in and select Disable.

Task Manager rates each app from what it measured at startup. High means more than 1 second of processor time or more than 3 MB of disk activity; Low means less than 300 milliseconds and less than 292 KB. Start with the High entries: chat and meeting apps you open by hand anyway, game launchers, and updaters for software you rarely use. Keep your security software, the utilities that make hardware work (touchpad, audio, docking) and any sync client you rely on.

Disabling only stops the automatic start; the app still opens when you select it. The same list, with plain on and off switches, is in Settings > Apps > Startup.

Close heavy apps and remove the ones you never use

Having many apps or browser tabs open can slow performance, so close anything you are not using right now. Then remove what you never use at all, because an app that is installed can still run in the background and take disk space.

1. Select Start > Settings > Apps > Installed apps.
2. Find the app, select More options (…), then Uninstall.
3. For older desktop programs that Settings will not remove, use Control Panel > Programs > Programs and Features, right-click the program and select Uninstall.

Some apps are built into Windows and cannot be uninstalled; leave those. On a new PC, the maker's utilities and trial software are the usual candidates, and setting up Windows on a new computer goes through them.

A preinstalled trial security suite deserves a decision rather than neglect. Microsoft Defender Antivirus turns itself off when a compatible non-Microsoft antivirus is installed, so while that suite is installed, Defender is not the one protecting you. If you do not plan to pay for it, uninstall it, then check that Windows Security > Virus & threat protection shows Defender is on. Whether Defender is enough on its own is covered in choosing antivirus software for your PC.

Free up space on the system drive

When a drive runs out of space, you may notice slower performance or trouble installing Windows updates. To see how much is left, open File Explorer and select This PC. In Settings > System > Storage, the capacity bar turns red when Windows considers the drive low.

Pick the quickest option that works for you:

1. Storage Sense, now: Start > Settings > System > Storage > Storage Sense > Run Storage Sense now.
2. Temporary files: on the same Storage page, select Temporary files, tick what you recognize and select Remove files.
3. Disk Cleanup: select Start, type Disk Cleanup, open it and choose the drive. Its Clean up system files button rescans the drive for system files as well.

Then turn Storage Sense on, so this happens without you. It is off by default. With its default settings it runs when the drive is low on space, removes temporary files and clears Recycle Bin items after some time, and it does not touch your Downloads folder unless you tell it to. It works on the system drive only, usually C:.

Tame the browser: tabs, extensions and sleeping tabs

Tabs are the easiest resource to waste. Google's own help puts it plainly: the more tabs you have open, the harder Chrome has to work. Three habits keep it in check.

Close tabs, and switch off extensions you do not use. Every extension is a small program running inside the browser.

• In Chrome, select More > Extensions > Manage Extensions and turn off or remove each extension you do not use.
• In Edge, select Extensions next to the address bar, then Manage extensions, and use the toggle to turn one off.

Let the browser put background tabs to sleep.

• In Chrome, select More > Settings > Performance and turn on Memory Saver. Choose Moderate, Balanced (recommended) or Maximum; the stronger the level, the sooner idle tabs are deactivated.
• In Edge, select Settings and more > Settings > System and performance > Performance and keep Automatically put tabs to sleep on. By default a background tab sleeps after two hours of inactivity; pick a shorter time under Put inactive tabs to sleep after a set time.

The two work slightly differently. Edge's sleeping tabs freeze a tab: its script timers pause, its processor use drops to a minimum and some of its memory is released, so switching back is instant. Chrome's Memory Saver deactivates the tab, and it reloads when you return to it. Neither puts a tab to sleep while it plays audio or shares your screen, so a call or a video keeps running.

Find the one heavy tab. In Chrome, select More > More tools > Task Manager, select Memory to sort, then select the task and End Process; unsaved work in that tab is lost. In Edge, Settings and more > More tools > Performance opens the performance detector, which lists background tabs using a lot of memory or processor time and lets you sleep or close them.

Check the power mode

Open Start > Settings > System > Power & battery, and under Power mode choose a mode for Plugged in and for On battery: Best power efficiency, Balanced or Best performance. Best performance helps the processor run at higher performance when needed, and Microsoft warns of the cost: more power use, faster battery drain and a laptop that may run warmer. Best performance when plugged in and Balanced on battery is a sensible pair.

If the setting will not change, a custom power plan is probably selected: open Control Panel > System and Security > Power Options and select Balanced. On a laptop, remember that browsers save power on battery too. Edge's energy saver follows the Windows battery saver setting, and Chrome's Energy Saver works when the laptop is unplugged or the battery is low; both trade some speed for battery life.

Run a quick scan with Microsoft Defender

Malware can consume processor and disk resources like any other program, and some potentially unwanted apps secretly use a PC for cryptomining. A quick scan is the first check, and it runs while you do the last step:

1. Select Start > Settings > Privacy & security > Windows Security > Virus & threat protection.
2. Select Quick scan, leave it running and move on. When it is done, Windows Security tells you if it recommends a deeper scan.

If the scan finds something, or the PC behaves in ways you cannot explain, open Scan options and run Microsoft Defender Antivirus (offline scan). It restarts the PC and scans without loading Windows, so persistent malware has a harder time hiding; save your work first. If the PC uses another antivirus product, run that product's scan instead, because Defender is switched off while it is installed.

Look for one runaway process in Task Manager

A single process stuck at high processor use slows everything else down, and Task Manager shows it at a glance.

1. Press Ctrl + Shift + Esc and stay on the Processes page.
2. Select the CPU column header so the heaviest process is at the top. Do the same with Memory and Disk.
3. Look for one entry that stays near the top while you are doing nothing.

If it is an app you opened, save your work in it, right-click it and select End task, then reopen it. If you need it to keep running, right-click it and select Efficiency mode instead: Windows then limits the resources that process can use so the apps in front of you stay responsive, and a green leaf icon marks it. Microsoft notes that it can make some processes unstable, so undo it if the program misbehaves. Do not end Windows processes you do not recognize; the quick scan you just started is the right check for an unfamiliar name.

Finally, if Windows Update asked for a restart, select Start > Power > Restart now. That completes the pass.

On a Mac: the same pass in five steps

A slow Mac responds to the same logic, with Apple's tools:

1. Restart. Choose Apple menu > Restart, and deselect Reopen windows when logging back in if you want a clean start.
2. Update. Open Apple menu > System Settings > General > Software Update and install what it offers.
3. Login items. In System Settings > General > Login Items & Extensions, select each item you do not need and click the Remove button below the list. Turn off background permission for apps that do not need it.
4. Storage. Check System Settings > General > Storage, delete what you no longer need from Downloads, and empty the Trash: deleted files keep their space until you do.
5. Activity Monitor. Open it, click the CPU or Memory column heading to sort, select the process at the top, click the Stop button in the upper-left corner and choose Quit. Force Quit ends it immediately but can lose unsaved data.

When quick wins are not enough

If the PC is still slow after a full pass, the cause is not clutter. Microsoft's own performance guide says that older PCs with outdated hardware may not see significant improvement from these steps, and that upgrading the device may then be the best long-term answer. To understand why a computer slows down in the first place, and confirm which resource is short, read why is my computer so slow. Three places to go from here:

• To tune each Windows setting properly (background apps, visual effects, virtual memory, Game Mode), read how to optimize PC performance in Windows 11.
• To find out whether an SSD, more RAM, better cooling or a new PC is the answer, read upgrading your PC for better performance.
• If the slowness has one clear symptom, such as a slow boot, one slow app or a disk stuck at 100 percent, diagnose that symptom rather than repeating this list; and a PC that will not start, shows a blue screen or has no Wi-Fi has a fault to troubleshoot, not a speed problem.

If the same laptop slows down every few weeks, or you look after more than a handful, that is a pattern worth fixing once. Our IT support service puts an engineer on the line when a laptop stops working, keeps devices patched and configured from one console, and traces recurring issues to their cause so they are fixed at the root rather than reset again next week.