How would you know if your computer is infected with malware

How do you know if your computer is infected with malware?

1. Your computer may perform slow.
2.Unexpected popup ads may appear in the browser.
3.The computer may crash frequently, freeze or BSOD (Blue Screen of Death).
4.Storage may be reduced unexpectedly.
5.System resource usage may increase, processor fan noise may increase.
6.Browser homepages may be changed without your permission.
7.New toolbar extensions or plug-ins can be added automatically.
8.Anti-virus activity may be stopped.
9.System updates may be turned off.
10.All computer information can be encrypted (Ransomeware attack).
11.Harmful programs can be hidden in the system and can smuggle all your

important information. Hacking on the other end can spread malicious programs into the hands of hackers or into other systems.