This is why I do not like all-in-wonder programs, preferring to use individual programs for AV/AT/AS/Firewall. It is much easier to diagnose issues if the services are not monolithic.
Furthermore, Most of the services provided by these programs need not run all the time- AV and firewall, surely, but for most folks, the rest is superfluous. Not only does this cause the program to be inordinately invasive, stretching it's tentacles deep into every aspect of the OS, It is also, by it's nature, very heavy on resources.
I started using ZoneAlarm free version. Very good firewall. I was using PC-Cillin as my virus protection. My mistake has been getting sucked in to using the "paid" versions. Every year I can get both "paid" versions free with rebates. Unfortunately each is trying to take over everything. PC-Cillin 2008 would not even install with ZoneAlarm present. It would not continue installation until I took off Ad-Aware and SpyBot. After I resolve the current problem with PC-Cillin I'll probably get rid of it and go back to an earlier free version of ZoneAlarm and something like AVG antivirus. I have several other computers with the ZA/AVG programs and haven't had any problems.