Why My PC Suddenly Slow and How to Fix it?

Do you want to know why the PC suddenly slows down? Does your drive have enough space? This post will teach you how to solve this problem.


By Dervish / Updated on May 12, 2023

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User case: PC suddenly slows down

“Until last week, my PC was still operating normally. But today I suddenly went to open it, and when it started, it was too slow and too lazy to perform any operations. I can't play games and watch videos smoothly, and I can't even open the settings. Is this a virus or something else? My specifications are still up-to-date, and I don’t know if I still have enough storage space. Do you have any suggestions for me? Thank you”

Why is my PC suddenly slow in Windows 10?

Below, I have summarized for you the most common reasons that cause the PC to suddenly slow down.

☞ Windows and drives are not updated
☞ Malware or viruses
☞ Excessive accumulation of dust
☞ Too many background programs
☞ Installing many programs takes up memory

How to fix PC suddenly slow?

These are the solutions to the causes of the PC slowing down. I will show you one by one. You can fix it according to your own situation.

► Manually check for system updates

When you suddenly slow down while using your PC, it may be that Windows has a new version and needs to be updated. Ensuring that your computer has the latest Windows and the latest drive is essential to get the best PC performance. New Windows and drive updates provide performance improvements, and outdated operating systems may cause PC speeds to slow.

You can open the control panel in "Start", then click "Update and Security", in "Windows Update", select the "Check for Updates" to update Windows 10.

► Scan the PC with anti-virus software

If the computer is infected with malware and viruses, it will also slow down the speed of the computer. I suggest you run anti-virus software to scan your computer for viruses, and thoroughly remove viruses that may impair your computer's performance.

► Clean up the dust

The fan on the computer CPU is used to dissipate heat, but due to static electricity, it will attract a lot of dust. If it has not been cleaned for a long time, the air outlet will be blocked by dust and the PC will slow down. You can often clean up the dust to increase the heat dissipation efficiency of the computer. For details, you can check out: Clean Intel Heatsink + Fan for Lower Temperatures!

► End background program

Slow computer running is usually caused by too many programs running at the same time, which takes up processing power and reduces the performance of the PC. Even if some programs are closed, they will continue to run in the background or start automatically when you start the computer.

To see which background programs are running on your PC and how much memory and processing power they occupy, please open the "Task Manager", which you can access by pressing CTRL + ALT + DELETE.

► Uninstall infrequently used programs

If you did not experience any slowness when using the PC before, but the PC will slow down after downloading the software, it may also be due to the installation of too many programs and the memory space is full. When the memory is full, the PC will run slowly. At this time, it is recommended that you uninstall some infrequently used software to clean up the memory.

You can search for "Control Panel" in the search bar in the lower-left corner and then click "Uninstall a Program". Select the software that is not commonly used it to uninstall.

The above has introduced you to five quick ways to solve the PC suddenly slow, but if you want to keep the running speed of the PC continuously, these methods are difficult to meet your needs. You need to use some more advanced methods to make your computer faster.

Further reading: How to make your computer faster?

Below, I will introduce you to third-party software——AOMEI Partition Assistant Proessional. It is a professional disk management tool, the functions of extend system drive and migrate OS from HDD to SSD can help you improve the performance of your PC easily and quickly. Besides, there are other ways you can make Windows run faster. For example, 4K alignment, schedule defrag, etc.

Download Demo Win 11/10/8.1/8/7/XP
Secure Download

Extend system drive

Full system space will greatly affect the PC's reading and writing speed. If you do not have uninstallable software, then you can extend the system drive. The specific operations are as follows:

Step 1. Install and launch AOMEI Partition Assistant Pro. Then, all disks and partitions will appear on the main interface.

Step 2. In this demonstrator, there is unallocated space behind the C drive. Then, right-click the partition (here is C drive) you want to extend and select "Resize/Move Partition".

Step 3. In the pop-up window, position the mouse pointer on the right border of the partition and drag the border rightwards to extend the partition. Then click "OK". (If there's no unallocated space beside the partition, you could not drag the border).

Step 4. Then it will be back to the main interface and you could preview the C drive that has been being extended. Click the "Apply" on the toolbar to commit the operation.

Note: If there is no unallocated space on the system hard drive or adjacent unallocated space behind the system partition, please refer to how to allocate free space or how to merge partitions.

At this step, you have successfully extended the space of the system drive. Make your PC run faster. However, if you still want to pursue a faster read and write performance, please continue reading.

Migrate OS from HDD to SSD

As we all know, SSD has a faster read and write speed than HDD. If your computer uses an HDD and you want a qualitative improvement in the running speed of your PC, then I suggest you upgrade to a better SSD. You only need to migrate the OS on your existing PC to SSD to use it.

Step 1. Install and open AOMEI Partition Assistant Pro on your Windows 10 computer. Click Migrate OS” in the top panel and click “Next.

Migrate OS to SSD

Step 2. Here, you need to choose an unallocated space on the SSD drive and click Next to continue.

Select Space on SSD

Step 3. In this window, you are allowed to resize partition or specify the location of the partition created on the SSD drive. Then, click “Next”.

Resize Partition

Step 4. Read it and clickFinish”.


Step 5. In the main interface, click “Apply”.


●After migrating OS to SSD, to boot computer from the new SSD drive, you have to enter BIOS settings and change the boot order to make the SSD the first boot device.
●If you are an enterprise user, it is recommended that you use the advanced version, such as AOMEI Partition Assistant Server.


Do you see? There are so many ways to solve PC suddenly slow, you can choose according to your needs. Through these operations, you no longer need to worry about playing games not smoothly or watching video freezes.

Dervish · Staff Editor
Dervish is an English editor of AOMEI Technology; He is delicated to offering users easy and effecitve solutions for issuses related to disks and partitoins. In his spare time, he enjoy wathcning films, playing footable, traveling and so on.