List signs of virus and malware infection.

What will be an ideal response?

• An unusual message or image is displayed on the computer screen.• An unusual sound or music plays randomly.• The available memory is less than what should be available.• A program or file suddenly is missing, or an unknown program or file mysteriously appears.• The computer's security tools, such as antivirus software or firewall, become disabled.• The size of a file changes without explanation.• A file becomes corrupted.• A program will not run.• The computer operates much slower than usual.• Your browser displays pop-ups that you cannot close or webpages you did not request when you are online.