Which of the following are common symptoms of computer viruses? (Select the three best answers.)

A common symptom of computer viruses is that a computer runs slowly. This can occur because viruses often consume system resources, causing normal applications to lag and overall system performance to degrade. When a virus is active, it might also be executing background processes that take up memory and processing power, leading to this noticeable slowdown.

Locking up or freezing can also be a sign of a virus, as the malicious software may interfere with the operating system's ability to manage its resources effectively. This disruption can halt all processes, causing the computer to become unresponsive until restarted, which is indicative of potential viral activity.

Another frequent indicator of viral presence is the appearance of excessive pop-up windows. These pop-ups often serve ads or attempt to deceive users into clicking on malicious links, which can further compromise the system.

Additionally, if a strange website is displayed whenever a search is performed, this could suggest a hijacking of the browser settings, a tactic often used by certain types of malware, including viruses.

Unusual error messages can also point to viral activity as these messages may be generated by infected applications or the operating system itself stressed by malicious processes.

All these symptoms together create a comprehensive picture of how viruses can affect a computer's operation, making them essential indicators for identifying