You bet Pureblood, If the Firewall is no longer active, ensure for now the XP firewall is enabled
I like either of these free AV's
AVG 7 by GrisoftOR
Avast Home Edition by ALWILI have
Avira's AntiVir (FTP download mirrors not reliable) on another computer I have, I don't think the free version has an email scanner
It's a very good AV, but you would have to ensure you scan email attachments manually before you open them
It's good practice to do that anyways, so this way, I find AntiVir just as good
ONLY use one AV, more than one can cause conflicts and system Instabilities
I'm sure you know that
You can find links to these free tools
HEREThere are also links to free Firewalls on that same page
Have a peek, many users going with either Kerio or ZoneAlarm
Save the installers to desktop
Remove all of McAfee's>>Reboot
Install your new AV>>reboot if required
and then your new Firewall>>reboot if required
After installation of new Firewall, by default it should disable XP's firewall
You also only want one Firewall running
I hope that helps