This is often a fake virus alert or scam notification, not a Microsoft message. Rogue security software and fake virus alerts are designed to scare users into clicking or paying.
Try this in order:
- Force-close the browser window showing the alert.
- Press Ctrl + Shift + Esc to open Task Manager.
- Select Microsoft Edge or the browser showing the message.
- Select End task.
- Remove the site notification permission and clear browser data.
- In Edge, go to Settings > Cookies and site permissions > Notifications.
- Remove any unfamiliar sites.
- Clear cookies and cached files.
- Run a full malware check.
- Open Start > Settings > Update & Security > Windows Security > Virus & threat protection.
- Under Current threats, select Scan options.
- Run Windows Defender Offline scan.
- Save work first, because the PC restarts before the scan begins.
- If the same malware keeps returning after restart, use Microsoft Defender Offline again. It scans outside Windows and can catch hidden threats that reinstall malware.
- If malware has caused irreversible changes, back up needed files and consider resetting the PC. Restore files from backups created before the infection when possible, because backups stored on the PC during infection might also be affected.
To reduce the chance of this happening again:
- Use Microsoft Defender Antivirus or Microsoft Safety Scanner to detect and remove trojans.
- Avoid opening attachments from unfamiliar senders.
- Keep Microsoft Edge SmartScreen enabled.
- Keep Windows updated.
- Troubleshoot problems with detecting and removing malware
- Microsoft resources and guidance for removal of malware and viruses
- Trojans
- Protect my PC from viruses
- How to get rid of virus notice? d155420ko90s739jn0vg.xso-adguard.co.in - Microsoft Q&A
- Troubleshoot problems with detecting and removing malware