Get 4.5 branch; I have not had good luck with the newer versions on Win98 computers. This is a very basic firewall. It was released in 2004 and can not stop everything but the newer versions seem to cause crashes for win98 computers. It has a good startup walk through, don't skip it. It will be a pain at first but will run unnoticed once you set it up with your programs. There maybe better firewalls out there but I can only say what has worked for me. 3 of the computers I installed the newer versions in locked up completely and one computer ran for 2 weeks and then started turning itself on when no one was around. Pulled the newer versions out and all computers were fine. Re-installed older version and all is well. An old firewall is better than no firewall.
Hey I got a win 98 machine and having great diff finding firewalls compatible with win 98.
Suggestions warmly welcome!