Disconnect the device from the internet
Back up important files to an external drive
Boot into Safe Mode
Run a full scan with updated antivirus software
Remove or quarantine detected threats
Uninstall suspicious programs
Delete suspicious browser extensions
Clear temporary files and browser cache
Update the operating system and all software
Change important passwords from a clean device
Enable a firewall
Restore the system from a clean backup if needed
Reset the device if the infection cannot be removed