ThreatFire

ThreatFire is a different antivirus, while other antivirus work based on a list of virus, ThreatFire works and scan your computer looking for and detecting malicious behavior, such as capturing your keystrokes or stealing your data, instead of only looking for known threats.

By that way, ThreatFire can fight versus virus and spyware from zero-day, from the first moment it tries to do malicious activity, you'll be protected, no matter if it is known or unknown spyware, adware, keyloggers, viruses, worms, Trojans, rootkits, buffer overflows,...

That means that even if you already have an antivirus working on your system, Threatfire is useful, a bit of help for your antivirus is always welcome.

Finally, it is totally free and it does not consume a lot of resources, so we recommend you to give it a try it can prevent a crash, do you need any other reason?