What slows down a PC and how to fix it

A slow PC usually comes from one of four things: too many programs running at startup, a hard drive that is nearly full, malware or unwanted software taking resources, or a hard drive that is aging and fragmented. You can fix most of these yourself in an afternoon without buying new hardware.

The fastest improvement usually comes from stopping programs you do not use from launching when Windows starts. The second-fastest comes from freeing up disk space. After that, a malware scan and a restart often bring noticeable speed back. If your PC is more than five years old and still uses a traditional hard drive (not a solid-state drive), the drive itself may be the bottleneck, but you can test that before spending money.

Key Takeaways

  • Disable startup programs through Task Manager (Windows) or System Preferences (Mac) to prevent them from slowing down your boot time and background performance.
  • Delete old files, empty the Recycle Bin, and uninstall programs you no longer use to free up disk space, which directly improves speed.
  • Run a full malware scan using Windows Defender (built into Windows) or a free tool like Malwarebytes to catch unwanted software consuming resources.
  • Restart your PC after making changes—this clears temporary files and resets memory, often producing an when ready speed boost.
  • If your PC is over five years old and still uses a traditional hard drive, upgrading to a solid-state drive (SSD) will produce the largest single improvement.

Disable programs that launch at startup

When Windows starts, it automatically opens programs you may have installed months or years ago. Each one consumes memory and processing power even if you never use it. Stopping them from launching is one of the fastest ways to speed up your PC.

On Windows 10 or 11: Right-click the taskbar at the bottom of the screen and select "Task Manager." Click the "Startup" tab. You will see a list of programs with a "Status" column showing "Enabled" or "Disabled." Right-click any program you do not use regularly—Spotify, Adobe Reader, Zoom, antivirus tools you replaced, printer software—and select "Disable." You do not need to uninstall them; you are just stopping them from launching automatically. Close Task Manager and restart your PC.

On Mac: Click the Apple menu, select "System Settings," then "General," then "Login Items." You will see two lists: "Allow in the Login Window" and "Open at Login." Select any program in the second list and click the minus button to remove it. Restart your Mac.

After restart, your PC should boot faster and feel more responsive. If you ever need one of those programs again, you can launch it manually—disabling startup does not prevent you from using it.

Free up disk space by deleting unnecessary files

A hard drive that is nearly full runs slower because the operating system has less room to write temporary files. Freeing up space is straightforward and produces when ready results.

Start by emptying the Recycle Bin (Windows) or Trash (Mac). Right-click the Recycle Bin icon on your desktop and select "Empty Recycle Bin." On Mac, click the Trash icon in the dock, then click "Empty Trash." This alone may free up several gigabytes.

Next, uninstall programs you no longer use. On Windows, open "Settings," go to "Apps," then "Apps & Features," find a program you do not use, click it, and select "Uninstall." On Mac, open "Applications" in Finder, drag unused programs to Trash, then empty Trash. Uninstalling removes not just the program but also the files it installed.

Finally, delete old downloads and documents you no longer need. Open File Explorer (Windows) or Finder (Mac), navigate to your Downloads folder, and delete files older than a few months. Check your Documents folder and Desktop for files you can remove. If you are unsure whether you need something, move it to an external drive or cloud storage first rather than deleting it permanently.

Run a malware scan to remove unwanted software

Malware and unwanted programs can run invisibly in the background, consuming CPU and memory. A malware scan takes 30 minutes to an hour and often reveals programs you did not know were there.

On Windows: Windows Defender is built into Windows 10 and 11 and is free. Click the Start button, type "Windows Defender," and open "Windows Security." Click "Virus & threat protection," then "Scan options." Select "Full scan" and click "Scan now." Your PC will scan every file on the drive. This takes time—let it run while you do something else. When it finishes, it will show what it found. If it detects threats, click "Remove" or "Quarantine."

On Mac: macOS does not include a built-in malware scanner, but Malwarebytes offers a free version. Visit malwarebytes.com, read the Mac version, install it, open the program, and click "Scan." Let it run to completion.

After the scan finishes, restart your PC. Malware removal often produces a noticeable speed improvement because those programs are no longer running.

Restart your PC to clear memory and temporary files

A restart clears your PC's memory (RAM) and deletes temporary files that accumulate while you work. Even if you have not made any changes, restarting a PC that has been running for weeks often makes it feel noticeably faster.

On Windows, click the Start button, click the power icon, and select "Restart." On Mac, click the Apple menu and select "Restart." Let your PC fully shut down and boot back up. Do not put it to sleep—a true restart clears more than sleep mode does.

After restart, open only the programs you need right now. Avoid opening 10 browser tabs, Spotify, Discord, and email all at once. Each program you open consumes memory. If your PC feels slow again after a few days, another restart will help.

Check your disk space and storage type

Your PC's speed depends partly on how much free space you have and what type of drive it uses. You can check both in a few seconds.

On Windows: Right-click "This PC" or "My Computer" on your desktop or in File Explorer, select "Properties," and look at the "Storage" section. You will see a bar showing how much space is used and how much is free. If the bar is more than 80 percent full, your PC will run slower. Delete more files or move files to cloud storage or an external drive to free up space. Below the bar, you will see the drive name and type. If it says "SSD" or "Solid State Drive," you have a fast drive. If it says "HDD" or just shows a drive letter with no type listed, you likely have a traditional hard drive, which is slower.

On Mac: Click the Apple menu, select "About This Mac," then click "Storage." You will see a colored bar showing how much space is used. If the bar is mostly full, delete files to free up space. The storage type is listed below—look for "SSD" or "Solid State Drive." If you do not see that label, you have a traditional hard drive.

If your PC is more than five years old and uses a traditional hard drive, upgrading to an SSD will produce the largest single speed improvement. An SSD costs between $50 and $150 depending on size, and installation requires opening your PC or taking it to a technician. This is a bigger project than the steps above, but it is the most effective long-term fix for an aging PC.

Adjust visual effects and background processes

Windows and Mac both use visual effects—animations, shadows, transparency—that look nice but consume processing power. Turning some of them off can speed up an older PC.

On Windows 10 or 11: Right-click "This PC" or "My Computer," select "Properties," then click "Advanced system settings" on the left. In the window that opens, click the "Advanced" tab, then click "Settings" under "Performance." A new window will open with a list of visual effects. Select "Adjust for best performance" to turn off most effects at once. This makes Windows look plainer but noticeably faster. Click "explore," then "OK."

On Mac: Click the Apple menu, select "System Settings," then "General," then "Accessibility." Scroll down and look for "Display" options. Turn off "Reduce motion" and "Increase contrast" if they are on—these can slow older Macs. These changes are subtle, but they help.

You can also reduce the number of browser tabs you keep open. Each tab in Chrome, Firefox, or Edge consumes memory. Close tabs you are not actively using, and consider using an extension that suspends inactive tabs automatically.

Frequently Asked Questions

How much faster will my PC be after I do these steps?

The improvement depends on what was slowing it down. If startup programs were the problem, boot time may drop from two minutes to 30 seconds. If your drive was nearly full, overall responsiveness may improve by 20 to 40 percent. A malware scan can produce dramatic improvements if unwanted software was running. Most people notice a clear difference after restarting.

Is it safe to disable startup programs?

Yes. Disabling a startup program does not uninstall it or break it. You can still launch it manually whenever you need it. The only programs you should be cautious about disabling are security software like antivirus or Windows Defender, though even those can be disabled if you replace them with another antivirus tool.

What if my PC is still slow after I do all of this?

If your PC is more than five years old and uses a traditional hard drive, the drive itself is likely the bottleneck. An SSD upgrade will produce the largest improvement. If your PC is newer, the issue may be hardware—not enough RAM, an overheating CPU, or a failing drive. You can check CPU temperature with a free tool like HWMonitor (Windows) or Macs Fan Control (Mac). If temperature is above 80 degrees Celsius during normal use, your PC may need cleaning or thermal paste replacement.

Do I need to buy software to speed up my PC?

No. Windows Defender and the built-in tools in Windows and Mac are sufficient. Paid "PC optimizer" software often does the same things these free tools do, and some can cause problems. Stick with the steps in this guide and free tools like Malwarebytes.

How often should I restart my PC?

Restarting once a week keeps your PC running smoothly. If you notice slowness building up after a few days, restart sooner. Leaving your PC on for weeks without restarting allows temporary files and memory usage to accumulate.