Hello Yile, welcome to MalwareTips.
I hope you like it here and stay active.
You should post your security configuration since you haven't had malware infection for awhile.
I'm sure others here would like to see it.
I’m glad to share some experience with all of you, here are some tips may help you :
1. Security software is essential
An antivirus software is not able to protect you from all threats from the internet, but it can help you a lot. Since there are so many free antivirus software in the world, why not pick up one and install ? For me, I use Avira Free antivirus, because it is powerful and it does not slow down your system. Other free or paid antivirus software is also very good choices, such as "Qihoo 360", "avast!", "AVG", "Panda", "Bitdefender", "Kaspersky", "Norton", etc. But keep in mind that you should only keep one antivirus software active in your system, double or multiple antivirus software active may cause problems. A firewall is also important. For me, I use Windows Firewall, because it is powerful against incoming attacks. And other third party firewall is also good choices, such as "Comodo", "Outpost", "ZoneAlarm", "Private Firewall", etc. And do not forget that only one firewall software is allowed in one system.
2. Use VirusTotal before you run an unknown application
I think it is the most important tip. VirusTotal is a website which provide multiple engine scanning service from different security vendors. In other words, you can upload a suspicious file and your file will be scanned by various scanning engines. After that, you will see a report of which engine determine it as a virus. So it is a good reference for us, and it is free, you can use it at any time. Here is the website:
https://www.virustotal.com/ .
3. Do NOT ignore phishing site
Phishing site can be more harmful than virus, it may cause real money loss. Some vendors may claim that their antivirus software contains antiphishing function, but it dose not work every time, because the number of phishing sites increases quickly. Always keep an eye on the URL, and you can detect phishing sites by yourselves.
4. Upload suspicious file to your antivirus vendor
If you think an antivirus software missed a virus, you can upload the file to the antivirus vendor for analysis, and it can help other people who use this antivirus software. That's what I usually do.
Here is some tips I would like to share with you, and I will upgrade it if some new ideas come to my mind.