The only thing with running more than one anti-virus software and more than one firewall (those spyware finders/deleters don't matter, some find different ones that others can't) is that it uses tonnes of memory and system resources, so unless you got lots of that to spare I wouldn't recomend using more than one. With firewalls sometimes they overide each other (like the Windows firewall and Trend Micro firewall) and that can create problems by thinking the other is a hacker or completely ignoring a real attack. I've acually had this happen to me and running more than one firewall was the problem.