More information for everyone.
I've received confirmation from Fortinet that this is a Trojan. According to the virus researcher there, Patrick Nolan, this is a variant of a family of Trojans named "QuickBatch", so named because it's a batch script compiled using a demo version of Quickbatch compiler (a compiler program that turns batch scripts into exe files).
Patrick confirms that this Trojan does delete files, though it does not appear to format the drive. Its file deletion routine consists of systematically deleting files not in use by Windows or any running applications/services, in all folders and subfolders.
Regards, -- Mary