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.
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Technical Details: Alexey Podrezov, F-Secure