It seems like you chose to install LILO onto a USB instead of the MBR on the hard drive during the installation process. I think installing LILO to the MBR should do it.
Once you're in the system (booting into the system with your USB LILO), running:
should (as far as I know) install LILO to the MBR.
Note: I've never installed LILO onto a USB or floppy disk, so although I doubt it, I'm not sure if the USB has contents from /boot like the kernel image, initrd, etc. that you may need.