I would say boot to DOS with a Windows 98 CD or a
Windows 98 bootdisk and run fdisk /mbr because that will destroy a boot sector virus. However, that will also destroy your Linux boot loader too. You'd have to re-install Linux if you did that.
Oh, and BTW. When you delete a partation you don't touch your MBR(Master Boot Record). So no matter how many times you blow off your partation(s) and no matter what OS you install you will not clean your boot record. You have to clean it manually(by methods like FDISK /MBR ).
Then again, you may not have a virus at all. Your virus scanner may think that the Linux boot-loader is a virus because it tampered with the MBR. Norton AV 2003 doesn't mis-identify a bootloader as a virus.
[ September 25, 2003: Message edited by: Viper ]