This is a boot virus. One unusual feature of this virus is that it infects both MBR and DBR on hard drives.
This virus also modified the CMOS settings of the machine in order to spoof a clean boot. Check that your drive A: settings are correct in CMOS Setup before booting clean and disinfecting the virus.
The code of the virus contains this text:
Otherwise the virus only spreads.
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Description Created: Mikko Hypponen, F-Secure