You can check files with the Virus Total online scanner at https://www.virustotal.com/
on the web. I like to see at least 2 of these AVs detect something before I believe it is infected: Avira, Bitdefender, Nod32, Kaspersky, or Sophos. You can report ClamWin false positive detections to the Clam AV project (ClamWin uses its own Windows port of the Clam AV Linux program) at http://www.clamav.net/contact
on the web. Be sure to select the correct link---report a virus, report a false positive detection, etc.