A computer is slow, unknown messages appear, and unknown applications open. What is the most responsible step?

Correct answer: Run a security scan and avoid suspicious applications

Slowness, unexpected messages, and unknown applications can be warning signs of malware, although they can have other causes too. A security scan is a measured first step, and avoiding suspicious links or programs prevents further harm. Sharing passwords or clicking messages is unsafe, while deleting everything without checking may destroy useful evidence and work.