Trojan.pandex on found on MAC

Hello,

 

Today, I downloaded Norton Atnivirus,Firewall and Confidential which was provided through Comcast. When I ran the scan, /Volumes/FreeAgentDrive/$RECYCLE.BIN/$RLY50z5.zip for Trojan.Pandex came up. The repair failed twice. Would you be so kind as to tell me what this is, how bad is it and how to remove the infected file. Thank you so much!