The infection described certainly does not come from file downloaded at CNET.
It is possible that you were redirected to another page when searching for AVG download.
If the computer is working now, could you please check browsing history from the day of infection for any suspicious links.
Should you need help removing the infection please provide us with GMER outputs:
Upload both outputs as described here:
We downloaded the free version of AVG from CNET. We left the computer downloading. The next time someone logged on, we had AV Security Suite running - this is a very nasty piece of malware that acts like a Trojan virus and has infected all kinds of things including the registry. I have been working on getting rid of it.
However, I do believe the malware came with this download. The .exe file was created the first time someone logged on right after the download.
I am not asking for Tech help, just reporting the problem. It is very troubling that we downloaded a well known piece of software from what we consider to be a safe site and ended up with malware taking over the computer.