8 Reasons Why Your PC is Slow

Preface: This post is designed for Windows, specifically Windows 10. The steps shown are virtually the same for Windows 7 (RIP, we will miss you 7), although there may be slight differences in terminology and settings locations.

You’ve had your computer for a year or so. You’ve done a lot on it, installing, removing, and using programs and files. One day, you log on and click on the Start button.

The cursor spins: 1, 2, 3, 4, 5 seconds.

The Start Menu finally opens. Why did it take that long when it used to be lickety-split? Here are six reasons why your computer might be slow and how to fix them, in order of least to most severe:

1. Your hardware is out of date

There are devices out there made with cheap, slow hardware. Be this an outdated Intel Celeron CPU, or a 5,400 RPM hard drive instead of a 7200 RPM or an SSD (solid state drive), it places a bottleneck on your system’s performance. Depending on how you look at it, this could qualify as #1 or #8. On one hand, you don’t have a serious data-threatening issue like malware, but it is an issue you’ll have to deal with until you spend money to fix it.

How to fix it: If you can afford to upgrade individual components or buy a new system, go for it! You’ll be impressed with the snappiness of newer hardware. If you can’t, continue reading this list to see some things that may help to slightly improve performance.

2. Have you turned it off and on again?

Did you know that most computer problems can be solved by simply restarting?

This is the question most tech support reps will ask first because it really works! Restarting your computer gets rid of unnecessary files in the RAM (random access memory). When programs are open for a long time, they have a tendency to load more files into the RAM, leaving it unavailable for other programs and slowing your system down

How to fix it: Restart your computer.

3. You have a lot of background programs running

See all those background processes? They can take a lot of valuable memory (RAM).

Over time, you install and remove programs. Sometimes those programs install other programs & helpers. Helpers start with Windows to…well…help a program do its job properly. However, when you have too many programs and helpers running, your CPU and RAM usage are nearest their peak, which is not ideal.

How to fix it: Open the Task Manager (Shift + Ctrl + Esc). Click the button at the bottom titled “More Details.” Click “Startup.” Observe the list and disable programs that aren’t necessary.

4. Temporary files have piled up

Properties of the User's Temporary Files Folder

Temporary files are different from files in the RAM. Both are technically temporary, but when a file is in RAM, it is actively being used or recalled. When a file is in the temporary folder, it is needed for a longer period than that of which RAM is useful. For example, Microsoft Office stores temporary backups of your files in case you need to recover unsaved changes. If these files were stored in RAM, they’d be gone the next time the computer restarts.

How to fix it: Open the Run dialog (Win + R). Type in “cleanmgr” and hit Enter. When the window opens, choose the appropriate drive and click OK. In the next window, you will see a list that contains categories like “Temporary Internet Files” and “Previous Windows Installations,” along with their respective sizes. Check the categories you’d like to clean (Recycle Bin can be a large one) and click “Clean Up System Files”. Enter your administrator password, if prompted.

5. Your drive is fragmented

Look at the "Fragments" column. The first file has 1,193 fragments! Not good!

To understand this one, you need to understand how drives store data. On a traditional hard drive, there are billions of teeny tiny sectors. Each sector can store one bit (either a 1 or a 0), depending on whether it is magnetized or not. Seven ones and zeros make a letter or number in the binary language. Repeat this process over and over and you can make a text file, video, photo, or website! But you can’t just store these bits all over the drive. They have to be able to be found again later on. To do this, your computer stores the data in an extremely orderly pattern. Here’s a quote from Explain That Stuff that sums it up nicely:

Part of the hard drive stores a map of sectors that have already been used up and others that are still free. (In Windows, this map is called the File Allocation Table or FAT.) When the computer wants to store new information, it takes a look at the map to find some free sectors. Then it instructs the read-write head to move across the platter to exactly the right location and store the data there. To read that information, the same process runs in reverse.

When you’ve used your computer for a while, files get deleted and new files replace them. Over time, you get small ‘pockets’ of free space, which the computer then fills with data. These are called fragments. The problem with fragments is that a single file could have data stored all over the drive (although it still shows up in your Documents folder as one file). When data is stored too far apart, the computer has to search for it, which takes longer than if the related data were stored nicely together. When you defragment your drive, your computer rearranges the fragments to seat them closer to each other, decreasing time required to find a file. Windows has a built-in program to defrag your drive, but its features aren’t as advanced as some other programs.

How to fix it: If you’d like to defrag your drive yourself, I recommend Defraggler. While it may look daunting at first, there are only a few options necessary to defragment your drive. Check back soon for a guide on how to defragment a drive with Defraggler. 

Be warned: the defragmentation process can take a while. I recommend you leave it running overnight and check on it in the morning. On my test PC, it currently estimates longer than 1 day, sitting at 2% completed. You will likely experience faster results than mine since the benchmark reported a frustratingly slow 780kbps read speed.

6. Your drive is near full

When free space gets close to 10GB, I purge my laptop of installers and other junk.

When your drive gets close to full, it tends to take longer to access system files. Make sure you have at least 5GB (gigabytes), ideally more, of space available for Windows to use freely.

How to fix: Delete unnecessary installers, duplicate files, or whatever you don’t need anymore. Anything you want to keep —especially larger files & folders and sentimental images— should be transferred to an external hard drive (I recommend the WD My Passport Ultra. It’s relatively inexpensive, and for the peace of mind it provides, I believe it’s totally worth it. I have 4 backups (three of which are full drive backups) on my external hard drive and still have plenty of space available

7. Default graphics settings are slowing down Windows

Disable all of these except "Smooth edges of screen fonts" to improve performance on low-end machines.

Windows (and other operating systems) include animations and transparency that make things look really cool. They look nice, but on lower-end devices like a budget netbook or a 10-year-old desktop, it just becomes a laggy mess while your computer tries to render it.

How to fix it: Open the Start Menu and type "Performance". Click on "Adjust the appearance and performance of Windows". In the window that opens, you will see a slew of options that all make Windows look pretty. Unchecking these will disable transparency, animations, shadows, and a few other things. Most of these options are fine to disable, although I would strongly suggest you leave "Smooth edges of screen fonts" enabled, as text can be difficult to read with it disabled.

8. Your computer is infected

Image from since I don't have malware on my laptop :D

If you’ve made it this far down the list and nothing’s helped, it’s time to consider whether this could be malware, bloatware, or a virus. Think about the programs you installed before your computer started running slowly. Was the program from a reputable company? Did you get it from their official website? Even so, some programs can still be a bit shady and install unwanted toolbars, start pages, and more that only slow your system even more and potentially sell your data to advertisers. There are also programs called cryptomining malware" that "mine" digital currency. I won't go into the specifics here, but this is incredibly taxing on your system, and can cause it to crash.

How to fix it: Use an antivirus to scan for unwanted adware, spyware, bloatware, malware, and so on. I recommend using Malwarebytes in conjunction with their free AdwCleaner tool. Malwarebytes comes with a 14-day premium trial, but after that expires you can use it for free. If it detects anything, review the list to make sure it hasn’t caught any legit programs on accident (they usually show up as a Potentially Unwanted Program). Then click on “Quarantine Selected”. After that, it’s a good idea to visit the quarantine section and delete anything malicious permanently. Then reboot your device to finish the process. If you're unsure of what to get rid of, contact me and I can take care of it for you.

Final Words:

If these steps helped you out, I’d love to hear about your experience in the comments section below!

If after trying the ideas listed above your computer is still sluggish, head over to the Contact page, let me know the issue, and we'll work together to solve it.

Make sure to follow @ianboguetech on Twitter for updates whenever I post a new blog post! See ya!

This article was updated on February 3, 2020

Ian Bogue

Ian Bogue

I am Ian Bogue. I’ve been associating myself with technology since the late 2000s, and my passion only keeps growing. It’s my mission to provide you with quality tech assistance at a competitive price. I’ve lived in Southern California my whole life and know the area well. I provide my services from Castaic to West Hills to San Dimas and everywhere in between. As a student, my available time is limited, so please be understanding about my packed schedule! See ya!