Ok. I have sort of read through the forum and get an impression that BOClean and TDS are two of the better AT. Now I would like to list out my needs and see how both AT handles them. What I need is just yes or no. 1. super low resource usage (2MB to 4MB)? 2. frequent update (at least once a day)? 3. if possible, replace firewall all together. All I want is to block a trojan horse or trusted software to hijack another trusted software to send data out, i.e. outbound protection or other injection methods. Outbound detection that comes with the software firewall is a pain to use. Now, i have to delete the trusted list on every logout just in case I accidentally enable some trusted software which can be hijacked by the untrusted software. I thought that will be safe but may be it isn't. I am now using NOD32 and ZoneAlarm Pro (I know this one is probably not a good choice, but I did a test and installed many firewalls and this was the only one that passed all my test) with a backup KAV. But, as I have said, it is a pain to use.