Installing Win 7 on a Inspiron 1531 with Win 8.1

I am having trouble installing win7 on my inspiron 1531 which came with win8.  I should note that this computer can run win7 because there are drivers for it in the dell driver database for this model

I have an external dvd drive and load win 7. i am able to get the file loading screen, then i get to the "Starting WIndows" screen and it just hangs there. the dvd-rom stops spinning here.

I have tried several hard drives, knowing they are all in working order. the computer runs win8 fine. i also know the dvd drive works fine. i have the latest BIOS as well.

I get the same result if I try loading a win xp or vista OS as well. and i know my win7 disk works fine as well

googling this problem i come up with a bunch of people talking about UEFI and AHCI and legacy BIOS. I'm competent with computers but dont want to just turn off random stuff with no guidance.

can anyone help me please?