Quarantining the infected system is the most appropriate way to remediate the issue of an infection that the antivirus software cannot remove. Quarantining means isolating the system from the network and other devices to prevent the infection from spreading or causing further damage. Quarantining also allows the technician to perform further analysis and removal of the infection without risking the security of other systems or data.
Some of the steps involved in quarantining an infected system are:
Disconnect the system from the internet and any local network connections, such as Wi-Fi, Ethernet, Bluetooth, or USB.
Disable any file-sharing or remote access services on the system, such as Windows File Sharing, Remote Desktop, or TeamViewer.
Use a separate device to download and update the antivirus software and any other tools that may be needed to remove the infection, such as malware scanners, rootkit removers, or bootable rescue disks.
Transfer the updated antivirus software and tools to the infected system using a removable media, such as a CD, DVD, or USB flash drive. Scan the removable media for any infections before and after using it on the infected system.
Run the antivirus software and tools on the infected system and follow the instructions to delete or quarantine the infection. If the infection is persistent or complex, it may require booting the system from a rescue disk or using a Linux live disc to access and clean the system files.
After the infection is removed, restore the system to a previous clean state using System Restore, backup, or recovery partition. Scan the system again to ensure that it is clean and secure. Reconnect the system to the network and update the system and the antivirus software.
References:
How to Identify and Repair Malware or Virus Infected Computers, section 31 Uninstalling Antivirus Software, the Clean Way: 40 Removal Tools & Instructions, section 22 How to manually remove an infected file from a Windows computer3 The Official CompTIA A+ Core 2 Study Guide (220-1102), page 2194

The error message "Your connection is not private. Authority invalid." means that the web browser cannot verify the identity or security of the website's SSL certificate. This could indicate that the website has been compromised, has a configuration error, or has an expired or invalid certificate. The user should not proceed to the site or use a different browser, as this could expose their sensitive information to potential attackers. The user should also not reinstall the browser, as this is unlikely to fix the error and could cause data loss. The best action for the user to take is to report the error to the bank and wait for them to resolve it.

A battery backup, also known as an uninterruptible power supply (UPS), is a device that provides backup power during a power outage. When the power goes out, the battery backup provides a short amount of time (usually a few minutes up to an hour, depending on the capacity of the device) to save any work and safely shut down the equipment.

Explanation:
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