Questions: There are continuous popups that cannot be closed. The homepage, toolbars, and icons change without permission. Unexpected webpages open. Other people receive messages from you that you did not send. You cannot access the device's control panel. The computer crashes and displays errors. You are unable to shut down or restart the device.

The common signs that malware has been installed on a device include:

1. There are continuous popups that cannot be closed.
2. The homepage, toolbars, and icons change without permission.
3. Unexpected webpages open.
4. Other people receive messages from you that you did not send.
5. You cannot access the device's control panel.
6. The computer crashes and displays errors.
7. You are unable to shut down or restart the device.

Explanation for each option:

1. There are continuous popups that cannot be closed.

   • This is a common sign of adware or other types of malware that generate unwanted advertisements.

2. The homepage, toolbars, and icons change without permission.

   • Malware often changes browser settings and adds unwanted toolbars or icons.

3. Unexpected webpages open.

   • This can be a sign of a browser hijacker or other malware redirecting your web traffic.

4. Other people receive messages from you that you did not send.

   • This is a sign that your device might be part of a botnet or has a worm that sends messages without your consent.

5. You cannot access the device's control panel.

   • Some malware disables access to system settings to prevent you from removing it.

6. The computer crashes and displays errors.

   • Malware can cause system instability, leading to crashes and error messages.

7. You are unable to shut down or restart the device.

   • Some malware can interfere with system operations, including the ability to shut down or restart.

Incorrect options:

• There are no common signs of malware as all malware acts differently.

  • While malware can behave differently, there are still common signs that can indicate its presence.

• Your device's screen appears brighter.

  • This is not a typical sign of malware.

• Your device runs an automatic software update.

  • Automatic software updates are generally a sign of legitimate software maintenance, not malware.

• You receive a friend request from an unknown sender.

  • This is more likely related to social media activity rather than a direct sign of malware.

In summary, the correct signs of malware installation on a device include continuous popups, changes to the homepage and toolbars, unexpected webpages opening, unauthorized messages being sent, inability to access the control panel, system crashes, and inability to shut down or restart the device.