Quick answer
If your Windows computer is running slow, first check what starts with the system and what is using resources in the background. Then free up disk space, update the system and drivers, and turn off unnecessary visual effects. If the problem persists, check the health of the disk and memory.
How to recognize the problem
- The computer takes a long time to boot and sign in to the account
- Programs open slowly and often freeze
- The disk is constantly at 100% in Task Manager
- The browser and tabs work slowly
- The system becomes slower over time, without an obvious reason
Most common causes
Too many startup programs
Programs that start automatically with Windows use processor, memory and disk. These are often applications you do not use daily.
Not enough space on the system disk
When there is little free space left on the C drive, Windows cannot cache efficiently and work with virtual memory, so everything slows down.
Outdated drivers and Windows updates
Old drivers, especially for the chipset and graphics card, can cause slow performance and freezing. Unfinished updates also burden the system.
Malware and unnecessary programs
Adversarial software and optimization tools often run in the background and use resources. They can slow down the system and compromise security.
Hard disk failure or lack of memory
If the hard disk has bad sectors or the memory (RAM) is insufficient for your needs, the system will constantly read from the disk and run slowly.
Step-by-step fix
- 1
Check usage in Task Manager
Press
Ctrl + Shift + Escto open Task Manager. On theProcessestab, click theCPU,MemoryandDiskheaders to sort by usage. Pay attention to programs that constantly use more than 50% of the disk or processor. If you do not recognize a process, right-click and selectSearch onlineto check what it is. - 2
Disable unnecessary startup programs
In Task Manager, open the
Startuptab (in Windows 11Startup apps). Right-click a program you do not need and selectDisable. Do not disable drivers and security programs. Changes apply on the next system start. - 3
Free up space on the C drive
Open
Settings > Systemand the storage option (Storage), then turn onStorage Senseif it is not already. ClickTemporary files, review what is selected and delete temporary files, then remove unnecessary programs viaSettings > Apps(in Windows 11Installed apps, in Windows 10Apps & features). Aim to have at least 15 to 20% free space on the C drive. - 4
Update Windows and drivers
Open
Windows Updatein settings and clickCheck for updates. Install all available updates and restart the computer. For drivers, useWindows Update > Advanced optionsand the optional updates option or the official websites of the chipset and graphics card manufacturers. - 5
Turn off unnecessary visual effects
In the Start menu search, type
sysdm.cpland openSystem Properties. On theAdvancedtab, clickPerformance > Settings. SelectAdjust for best performanceor manually turn off animations you do not need, then clickApply. - 6
Check disk health
Open
This PC, right-click the C drive and selectProperties > Tools, then clickCheck. For a more detailed status, typeOptimize Drivesin search and check if optimization is needed: defragmentation for HDD, and TRIM for SSD (Windows usually runs it automatically). If Windows reports errors, immediately make a backup of your data. - 7
Scan the system for malware
Open
Windows Security > Virus & threat protectionand clickQuick scan. If needed, runScan options > Full scan. Remove all detected threats and restart the computer. - 8
Check memory and temperature
In search, type
Windows Memory Diagnosticand run the tool. The computer will restart and test the RAM. For temperatures and load, use trusted tools from the motherboard or graphics card manufacturer. Overheating can lead to slowdown (thermal throttling).
If nothing helped: deeper diagnostics
If all steps have been performed and the computer is still slow, check if the hardware is the bottleneck. A hard disk (HDD) as the system disk is a very common culprit for slow performance in 2026; switching to an SSD brings the biggest speedup. If you have less than 8 GB of RAM, upgrading to 16 GB is worthwhile for working with multiple tabs and programs. Also, check if Windows is installed on an HDD instead of an SSD. For advanced users: open Event Viewer and review Windows Logs > System for recurring errors. If the slowness occurs only in certain programs, the problem is probably in the application itself, not the system. In that case, update or reinstall the program.
How to prevent it
- Regularly install Windows updates and update drivers
- Keep at least 15% free space on the C drive
- Occasionally review startup programs and remove unnecessary ones
- Use only one antivirus program and scan the system regularly
When to call a professional
If the computer is still slow after all steps, or if you notice frequent blue screens, files disappearing or suspect a hardware failure, contact IT support. They can perform detailed diagnostics, check disk and memory health and suggest a cost-effective upgrade.
IT infrastructure maintenance · Servers, networks, backup, security and helpdeskFAQ
Is it safe to disable startup programs?
Yes, if you know what the program is for. Do not disable drivers, antivirus and system tools. If you are not sure, leave the program enabled or check the process name by searching the internet.
How much RAM is enough for Windows 11?
For basic work, 8 GB is enough, but for more browser tabs and office programs, 16 GB is recommended. If you often use demanding applications, 32 GB is a better choice.
Will deleting temporary files speed up the computer?
It can help if the disk was almost full. Freeing up space allows Windows to cache data more efficiently. If the disk is still full, delete unnecessary programs and large files.