There are many problems that your device may experience due to being infected with malware. Below you will find some common symptoms.
1) Pop-up ads and windows - Often, infected computers will start displaying pop-up messages. Many even indicate that your computer is infected and to "Click Here" for help. Do not click on these types of pop-ups as this is usually a scam trying to get you to purchase fake software to clean your computer.
2) Your browser homepage has changed and you did not change it - Many types of malware will either redirect your web browser or set the default web page to a site you are not familiar with.
3) You get ransom warnings - Possibly the worst form of malware. Cyber criminals that gain access to your computer can hijack your data, encrypt it, and demand a ransom to decrypt it and return it to you.
4) Programs that you did not install are on your computer - Sometimes malware will install software on your computer that you are not aware of. If you notice a new program that you did not install, you may have malware.