Until and unless you are not attacked by any virus or spyware you think that your computer security is very high but when your PC gets infected it is too late. So if you think that you have a good Internet security why not you go for some Internet Security Tests :
1) PopUp Blocker Test : This popup test is is an automated way to check your popup blocker's ability to allow good ads.
2) Firewall Test : This test will check your computer for ports that are commonly left open. Open ports could allow your computer to be compromised. This firewall test will also check for open ports known to be used by Viruses and Trojans.
3) Firewall Leak Tester : This website, on one hand, enables you to test your software personal firewall thanks to different test programs ('leaktests'), and on the other hand, shows a global vulnerabilities view of the most common personal firewalls in a summary page. Firewall Leak Tester provides also documentation and advices to improve your security dramatically.
4) Browser Security Check : This test will check your Browser Security. If you have good browser like Mozilla Firefox you will surely pass this test.
5) Online Port Scan : This test will make a scan of all your Open Ports.
If you have passed all these tests, congrats your system is VIRUSFREE