The presence of registry subkey HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\PINF may be indication of a Win32/Parite infection.
Win32/Parite is a polymorphic file infecting virus that infects all portable EXE and SCR files found on local and shared network drives.
What to do now
To detect and remove this virus, run a full-system scan with an up-to-date antivirus product such as the Microsoft Safety Scanner (http://go.microsoft.com/fwlink/?LinkId=212742). For more information, visit http://www.microsoft.com/athome/security/downloads/default.mspx