Hello, You can go to any independent antivirus tester such as: * http://www.av-test.org/en/ * http://www.av-comparatives.org/ You can do some more research on Google or any other search engine to find out what would be best for you. I want to warn you not to download anything from any site unless it is from the official site - for example if you are downloading Avira, do not download from any site other than http://avira.com/ Microsoft is not planning to release anymore updates for Windows XP, so it is recommended that you upgrade your operating system. That doesn't mean it won't still be usable however, you just need to be more cautious.