LILO saves a MBR backup as /boot/boot.0800. Before writing it back to the MBR make sure to not destroy the partition table contained inside LBA 0.
If you don't have a MBR backup, you can write a standard MBR that boots the active partition using
Code:
lilo -M /dev/sda mbr
Make sure, that the correct partition (the Windows 7 boot partition, which is not the C: drive) has the boot flag set.