The 'Trojan.Pif.Deltree' is a trojan in format of a PIF file. Being run under Windows this file will execute DELTREE.EXE file with '/Y *.*' command line which will result in deleting of all directories (except shared ones) on hard drive within seconds. The trojan will only work if Windows is installed to C:\Windows\ directory. Doesn't work under Windows NT and 3.xx.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
More information on scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.
Technical Details:Alexey Podrezov, F-Secure