The post by mchainmchain offers lists of uninstallers for you, but if I could ask.
You seem to be attempting to install anti-virus scanners when you already have Avast. AV scanners don't work well together and some may even attempt to prevent others from installing. Why do you want to install McAfee when you already have Avast?
Also, that "Avg_free_stb_all_2011_1388_cnet" file appears to be CNET's "Installer file" for AVG. It is not AVG itself. If you downloaded this file from CNET Download.com it should have been saved somewhere on your hard drive before you clicked it to run it.
Find that location where the download process saved the file, and delete it from there. This does not install anything onto the hard drive so I am at a loss why McAfee is flagging it as installed, and also as AVG.
CNet will not update my programs list - I keep getting
Results: Scan failed - Bad authentication response received from Server
Scanned on 01/01/2012
I need to remove Avg_free_stb_all_2011_1388_cnet which is not in my programs but McAfee will not install until AVG is removed - I am currently usingavast
this has gone on for several days - started when I was updating Playon with plugins and my entire system crashed - died - dead I was able to restore by backdating restore point - but things have not worked correct since - I spent 4 hours on with Verizon which was useless