Kerio 215 will give you random BSOD's involving fwdrv.sys
I know from personal experience when I was using Win2k which has no built in firewall.
Here are 2 that I came across in the days when I was hunting for a small footprint firewall:
http://www.ghostsecurity.com/ghostwall/
http://www.software4u.tk/
Ghostwall bills itself as a Windows Firewall replacement.
People claim ghostwall is unnecessary if you have a hardware firewall, claiming it basically does the same thing, but I'm no guru so can't comment. But when it was running I was unable to get Activesync to connect with my PDA and didn't know how to fix that. Ghostwall didn't show me any messages that it was blocking a connection (I managed to figure it out myself) and didn't want to subject myself to any other problems down the road so I just uninstalled this firewall after a while.
The AS3 website is a little shady, but it's on reputable website like softpedia and nonags.
http://www.softpedia.com/get/S...ersonal-Firewall.shtml
This program went from freeware to payware and back to freeware. Never tried it but it caught my attention due to claims of low resource usage and it's a small download. it has good user ratings from softpedia