Lenovo desktop win 8 will not load windows 7 as a dual boot
I have a new Lenovo Desktop computer preloaded with Windows 8. I want to dual boot with windows 7 HPrem. I create the new partion and start the install from win7 disk. on first reboot the boot loader screen comes up and says there is an unsigned driver. I disabled the detect unsigned driver in the bios but I can't get the win 7 to load. I have another lenovo desktop that came with Win7 and I loaded win 8 with no problem as a dual boot. What am I missing here??