SecurityRisk.OrphanInf
http://www.symantec.com/security_response/writeup.jsp?docid=2011-040403-3248-99
SecurityRisk.OrphanInf is a detection for autorun.inf files that no longer refer to a valid file on the compromised computer.
Autorun.inf files are configuration files that instruct the operating system which executable files to launch upon access. This is a popular infection vector for malware authors. Incomplete removal of threats can leave behind an orphaned autorun.inf file, which can prevent access to the compromised drive.