Did you download the right version?

http://www.comodo.com/home/internet-...t-security.php

I've installed this version only last week for someone and it didn't have Geekbuddy or Dragon with it. I think as you mentioned a 30 day trial, you downloaded the Pro paid for version. Just download the free one, and make sure you untick the options in one of the pages that installs advertisers extras like yahoo toolbar, and then it is perfectly fine. I have Comodo Internet Security running on older systems as old as an Athlon XP 3000+ with 1GB of ram and it runs perfectly well on there with no CPU resource hogging.

When I've seen a system scan do that with any security software in the past, a lot of the time there has been a bad infection on the system and the scanner locks up trying to deal with it and can't get past it, using 100% CPU.