Private Firewall, Privacy Software

I have been in search of a user friendly firewall for my notebook and have tried the free version of Zone Alarm and then purchased the Zone Alarm 5 Pro version.
both programs extremely slowed down my notebook both at start up and browsing. we gave the program a good try and our in house techie checked things out like to confirm our xp firewall was disenabled and as well checked the registry for suspicious entries and scanned the notebooks.
nothing could be found. even went to Hoovers site for help, no change in configuration helped.
thus my colleagues and i are looking for another firewall. we noted that this particular one is not a resource hog at 1.94 MB and is listed on your site. I only see mention of anything except free firewalls in most forums with kerio and sygate identified and I don't nor do my colleagues want to go down that road again. this Private Firewall seems user friendly and is not a resource hog. I understand that there is a newer version coming out with more bells and whistles in the near future.
However we are all relative novices at this, but not afraid to learn and yet on the other hand don't want to be messing around with configurations and rules in order to keep the computer running like it is now with the ZAP removed and the xp firewall engaged.
The notebook is a pentium 4, 1.9 ghz, 512 RAM with a mobile processor.
We would really appreciate comments from users of the Private Firewall and as well others from Novice users. Thankyou