Almost every day, a new type of computer virus is discovered, as well as new methods to covertly install the illicit software onto your system. Not only can a virus reduce the performance of your computer, but it can also corrupt important files, steal personal information or even encrypt your files before demanding a ransom payment. Although viruses and other malware tend to be extremely stealthy, there are several signs that indicate your system may be infected.
Poor performance: When your computer starts running slower than normal, taking a long time to start up, open programs or load websites, it may be a sign that viruses are running in the background. They tend to increase processor, memory, hard disk and Internet usage significantly, slowing down the system or even making it completely unusable.
Unusual advertisements or warnings: If you notice frequent pop-up ads on pages that should not have them, or somewhat official-looking windows that say your computer is infected and you don't recognize the program, your system may have a virus or the page may be trying to install one.
Disabled security software: Often, viruses will try to disable your antivirus software and firewall to prevent detection, while suppressing system warnings. If these programs stop working spontaneously, the system may be infected. The built-in firewall in Widows is frequently targeted, and upgrading to a more robust firewall may offer better protection.
Altered search or home page settings: Viruses often change important browser settings to earn money for their creators from click-fraud schemes and other advertising-related fraud, or to redirect you to sites that steal personal data. Beware of any sudden changes.
Unfamiliar programs: If you notice new software on the system that you have not installed, especially if it runs on startup, it could evidence of viruses. Research the name of the program to be sure.
To avoid virus infections, keep your operating system and software updated, and install quality antivirus and firewall software.