AVG free turned up trojan.dropper when Kevin ran it on his system. He also tried scanning with MalwareBytes which confirmed it, so that makes it more of a concern. He downloaded Microsoft Security Essentials and ESET and tried scanning with each of those, and didn't find anything. He only should have one antivirus installed at a time, because sometimes antivirus programs will find files in another antivirus program and flag it as a virus.
The only free antivirus that Leo recommends is Microsoft Security Essentials. Typically when infected with a virus the only way to be absolutely sure that the system is clean is to do a complete reformat and reinstall of Windows. Since ESET didn't find anything though, Leo thinks he's probably ok now, since ESET would even find root kits that a lot of antivirus programs don't detect.
(Disclaimer: ESET is a sponsor).