Conflicts can arise among software installations. I recommend that a user have no
more than one personal firewall installed on a computer. Not so much because of a
resulting possible crash but because it would be more difficult to configure and a
misconfigured firewall can be worse than no firewall having you believe you are
protected when you are not. The only good built in firewall would be the ICF firewall
in XP . If you are using that, it is a good firewall with the limitation being that
it can not manage outbound access. If you are talking about tcp/ip filtering , then I
think you should install a software firewall. If you are using XP ICF firewall and
want to use a software firewall for controlling outbound access also, I would disable
the ICF firewall and then install the software firewall while disconnected from the
internet.
I don't see a problem try two anti virus programs when you feel that their may be an
infection and your primary program did not detect anything. However for an ongoing
basis I would only have one program configured to "Auto Protect" and scan emails and
other files. You could uninstall the secondary program after being done with it.
There are also tools that strictly scan your computer for
viruses/worms/trojans/spyware that are not active until you initiate them which could
be left installed with no problem and used when necessary being sure to update
definition files before using. Sysclean from Trend Micro, available at the links
below, is an example of such a program. If you use additional virus scanning
programs be sure to disable your current primary program while doing the scan as it
may think that it is a malicious program. You should also always shut down your
personal firewall [after disconnecting from the internet] and antivirus program when
installing any software. --- Steve
http://www.trendmicro.com/download/dcs.asp
http://www.trendmicro.com/download/pattern.asp