I don't believe Sleepless was trying to be a jerk, a lot of people come on here trying to catch their significant other "in the act", so it's safe to say they were just trying to help you.
If this is a CP problem, then you should have asked this question in the "Porn and Laws" section.
However I'm curious, though, just exactly what your situation is. Are you trying to have proof that you did not search for this material, but that it somehow got on your computer? Because if that's the case, good luck. Our justice system seems to go as "guilty until proven innocent", or in other words, if the pictures are there, it's impossible that a virus put them there...even though, although rare, this has been proven to not be true.
However, if they found your computer to be sharing this material via Limewire, then it would not have been from a virus, but possibly an accidental download.
Again though, I kinda need your story to help you out. lol