Start with the easiest fixes first

A slow computer usually comes from one of three things: too many programs running at once, a hard drive that is nearly full, or dust clogging the cooling fans. You can fix all three without opening your computer or paying anyone. Start by restarting your machine — this closes programs that have been running in the background and clears temporary files from memory. If that does not help, move to the next step.

The second thing to check is how much free space you have on your hard drive. When your drive is more than 80 percent full, Windows and Mac both slow down because they cannot write temporary files smoothly. Open File Explorer on Windows or Finder on Mac and look at your storage. If you are close to full, delete old downloads, video files, or programs you no longer use. Moving files to an external drive counts as freeing space.

Key Takeaways

  • Restart your computer first — this closes background programs and clears temporary files without any work on your part.
  • Delete files until your hard drive has at least 20 percent free space, because a nearly full drive slows down both Windows and Mac machines.
  • Turn off startup programs that you do not use every day, because each one that loads when you start your computer adds seconds to boot time.
  • Dust buildup inside your computer blocks airflow and causes the processor to throttle itself down to avoid overheating, so cleaning the vents can restore speed.
  • If your computer is more than five years old and still has a traditional hard drive (not an SSD), replacing it with a solid-state drive is the single biggest speed improvement you can make.

Disable programs that start when your computer boots

Every program you install can ask Windows or Mac to launch it automatically when you turn on your computer. Most of these programs you will never use, but they all load into memory and slow down your startup time. On Windows, open Task Manager by pressing Ctrl+Shift+Esc, then click the Startup tab. You will see a list of programs with a Status column that says Enabled or Disabled. Right-click any program you do not need running all the time and select Disable.

On Mac, go to System Settings, then General, then Login Items. You will see two lists: Apps and Allow in the Login Window. Remove anything from the Apps list that you do not need to start automatically. Be cautious — do not disable programs you use daily, like antivirus software or cloud backup. The goal is to remove things like Spotify, Discord, or printer software that you open only when you need them.

Clean dust from your computer's vents and fans

Dust blocks airflow inside your computer, which causes the processor to overheat. When a processor gets too hot, it deliberately slows itself down to cool off — this is called throttling, and it can cut your speed in half. You can clean the outside vents with a can of compressed air, holding the can upright and spraying short bursts. For a laptop, spray the vents on the sides and bottom. For a desktop, spray the front and back panels where air enters and exits.

Do not shake the can, and do not hold it upside down — compressed air works only when the can is upright. Spray from about six inches away and use short two-second bursts. If your computer is more than two years old and you have never cleaned it, you may see a visible cloud of dust come out. After cleaning, restart your computer and feel whether the vents are warmer — that means air is flowing better and your processor is no longer throttling.

Check for malware and unwanted programs

Malware and adware run in the background and consume processor power and memory without you knowing. Windows comes with Windows Defender, which runs automatically, but you should run a full scan to catch anything that slipped through. Open Windows Security (search for it in the Start menu), click Virus and threat protection, then click Scan options. Select Full scan and click Scan now. This takes 30 minutes to an hour, so start it when you do not need your computer.

On Mac, malware is less common, but you can still check by opening Activity Monitor (search for it in Spotlight), clicking the CPU tab, and looking for programs using high processor power that you do not recognize. If you see something suspicious, search the program name online before closing it. You can also use a free tool like Malwarebytes to scan for adware that antivirus software sometimes misses. Run the scan and remove anything it finds.

Upgrade to a solid-state drive if you have an older computer

If your computer is more than five years old and still has a traditional hard drive (not an SSD), replacing it is the single biggest speed improvement you can make. A traditional hard drive has a spinning disk that reads and writes data mechanically — this is slow. A solid-state drive has no moving parts and reads data when ready. The difference is dramatic: a computer with a traditional drive might take 60 seconds to start up, while the same computer with an SSD takes 15 seconds.

You can buy an SSD for $50 to $150 depending on size, and many computer shops will install it for $50 to $100. If you are comfortable opening your computer, you can install it yourself — it takes 10 minutes and involves unscrewing one or two brackets and plugging in a cable. Before you replace the drive, back up all your files to an external drive or cloud storage. You will need to reinstall Windows or Mac on the new drive, which takes about 30 minutes and requires your Windows or Mac installation media or a recovery USB drive.

Close browser tabs and extensions you do not use

Web browsers like Chrome, Firefox, and Edge use a lot of memory, especially when you have many tabs open. Each tab is a separate process, and each one consumes RAM. If you have 20 tabs open, your browser might be using 2 to 4 gigabytes of memory — that leaves less for everything else. Close tabs you are not actively reading, and if you find yourself always keeping the same tabs open, use a bookmark folder instead.

Browser extensions also slow down your computer because they run in the background and monitor every webpage you visit. Open your browser settings and look at your extensions. Disable or remove anything you have not used in a month. Keep only extensions that do something you actually need — ad blockers and password managers are worth keeping, but most others are not. After you remove extensions, restart your browser and notice the difference in speed.

Increase virtual memory if you are running out of RAM

If your computer has less than 8 gigabytes of RAM, it may be running out of memory when you use multiple programs at once. You can see how much RAM you are using by opening Task Manager on Windows (Ctrl+Shift+Esc) and looking at the Memory tab, or Activity Monitor on Mac and looking at the Memory tab. If the number is consistently above 80 percent of your total RAM, your computer is struggling.

The best fix is to add more RAM, which costs $30 to $100 and takes 10 minutes if you are comfortable opening your computer. If you cannot upgrade RAM, you can increase virtual memory, which uses hard drive space as temporary RAM. On Windows, search for "Advanced system settings," click Environment Variables, then System variables, then New, and create a variable called PAGEFILE_SYS with a value of 2048 (for 2 gigabytes). This is slower than real RAM but better than nothing. On Mac, virtual memory is automatic and cannot be adjusted.

Frequently Asked Questions

Why does my computer slow down over time even if I do not install anything new?

Windows and Mac both accumulate temporary files, cache, and log files that build up over months. Dust also accumulates inside, blocking airflow. Restarting your computer regularly clears temporary files, and cleaning vents every six months prevents dust buildup. You can also use Disk Cleanup on Windows (search for it in the Start menu) to remove temporary files automatically.

Is it safe to disable startup programs?

Yes, as long as you do not disable antivirus software, cloud backup, or programs you use every day. If you disable something and your computer stops working the way you expect, you can re-enable it. Start by disabling programs you recognize and do not use daily, like Spotify or Slack.

How often should I clean the dust from my computer?

If you use your computer in a dusty environment or have pets, clean it every three months. In a normal office or home, every six months is enough. If you notice your computer getting hot or the fans running loudly, that is a sign dust has built up and you should clean it sooner.

Will adding more RAM make my computer faster?

Only if your computer is running out of memory. If Task Manager or Activity Monitor shows memory above 80 percent regularly, adding RAM will help. If memory is below 60 percent, adding RAM will not make a noticeable difference.

What is the difference between restarting and shutting down?

Restarting closes all programs and clears memory, then starts fresh. Shutting down does the same thing but also turns off the power. Both clear temporary files, but restarting is faster if you want to keep working. Shut down only if you will not use the computer for several hours.