Quick answer
If you suspect a virus or malware, first make a backup of important data, then proceed with cleaning. Use built-in tools like Windows Security and Malwarebytes, and if the threat persists, consider professional help. Never pay a ransom and do not delete files before saving them.
How to recognize the problem
- The computer is unusually slow, programs freeze or open by themselves
- Unknown windows, ads or toolbars appear in the browser
- Antivirus is disabled or cannot be updated
- Files are missing or changed without your knowledge
- You hear unusual hard disk activity or the fan runs constantly
Most common causes
Downloading from untrusted sources
Installing programs from unofficial websites, as well as crack or keygen files, often contains malware.
Phishing emails and fake links
Clicking a link in a suspicious email or message can lead to downloading malicious software.
Irregular system and application updates
Old versions of Windows, browsers and other programs have known vulnerabilities that malware exploits.
Unsafe extensions and add-ons
Browser or program add-ons installed without verification can be malicious.
Shared USB devices and network resources
Malware can be transferred via infected USB flash drives or shared network folders.
Step-by-step fix
- 1
Make a backup of important data
Before any cleaning, copy documents, photos and other important files to an external drive or cloud storage. Do not make a full system backup because you could transfer malware. Use
File Explorerand manually drag folders, or a sync tool if you already use one. - 2
Run a scan in Windows Security
Open
Windows Security(in Windows 11:Start > Settings > Privacy & security > Windows Security; in Windows 10:Start > Settings > Update & Security > Windows Security) and selectVirus & threat protection. ClickScan optionsand chooseFull scan, thenScan now. Wait for it to finish and follow the instructions to remove any threats found. - 3
Check if antivirus is disabled
If Windows Security reports that protection is off, open
Virus & threat protection > Manage settingsand turn onReal-time protection. If the option remains unavailable, malware may have changed settings. In that case, runWindows Securityas administrator or use another tool. - 4
Use another scanning tool
Download the free version of
Malwarebytesfrom the official website and install it. RunScan, thenScan now. Allow the program to remove any threats found. Do not run multiple antivirus programs at the same time as they may block each other. - 5
Clean temporary files and browser
Open
Settings > System > Storage > Temporary filesand delete unnecessary files. In Chrome, go toSettings > Privacy and security > Clear browsing data, and in Edge go toSettings > Privacy, search, and services > Clear browsing dataand remove cache and cookies. Also checkExtensionsand remove unknown ones. - 6
Check startup programs and tasks
Open
Task Manager(Ctrl+Shift+Esc), go to theStartuptab (in Windows 11:Startup apps) and disable unknown items. Then inTask Schedulerreview active tasks and disable suspicious ones, but do not delete system tasks if you are not sure what they are for. - 7
Update Windows and all programs
Open
Settings > Windows Update(in Windows 10:Settings > Update & Security > Windows Update) and clickCheck for updates. Install all available patches, then update the browser, Office and other applications. Regular updates close vulnerabilities that malware exploits. - 8
Change passwords from another device
If you suspect malware stole passwords, from another clean device change passwords for email, banking and other important accounts. Enable two-factor authentication where possible. This prevents abuse even if a password has leaked.
- 9
Restore the system to a previous state if needed
If problems persist, use
System Restore: in the Start search typesystem restoreand selectSystem Restore. Choose a restore point and follow the wizard. This option restores system files, drivers and programs, but not personal files, so they remain saved if you made a backup.
If nothing helps: advanced options
If malware remains active after all steps, you can try Reset this PC with the Keep my files option. Go to Settings > System > Recovery > Reset this PC (in Windows 10: Settings > Update & Security > Recovery) and select Keep my files. This will remove programs and return Windows to its initial state, but personal files remain. However, be sure to make a backup beforehand. If that also fails, a clean installation of Windows remains, which requires more time and expertise. Always keep in mind that prevention is the best protection: regular updates, caution with attachments and strong passwords.
How to prevent it
- Regularly update Windows and all applications
- Do not download programs from unknown websites and avoid crack files
- Enable two-factor authentication on important accounts
- Make regular backups of important data
When to call a professional
If symptoms continue after all steps, or if files are encrypted (ransomware), it is better to contact an IT expert. Also, if you are not sure how to make a backup or reset the system, seek help.
IT infrastructure maintenance · Servers, networks, backup, security and helpdeskFAQ
Will I lose data if I delete a virus?
No, if you properly remove the threat, personal files remain intact. However, some malware can encrypt or delete files, so a backup is crucial before cleaning.
How long does a computer scan take?
A full scan can take from 30 minutes to several hours, depending on disk speed and amount of data. A quick scan is shorter but may miss some threats.
Can I remove ransomware myself?
Ransomware is complex and dangerous; if files are encrypted, do not attempt to decrypt them yourself. Contact experts and do not pay the ransom, as it does not guarantee data recovery.