Multiboot failure / Non Complete Installation

Alright so yesterday i was trying to get windows 8 to work on multi-boot. so i made a new partition and the files copied over fine and then the computer restarted and it tried to continue installing but it encountered an error. so i assumed it needed more space because the partition was less the 25GB(which is what microsoft recommends). so i deleted all of the files from the old installation(so i could have a fresh install) and i made the partition bigger and then i ran the installer again. all the files copied over no problem but when the computer restarted i did not have the option to choose windows 8 or windows 7 it just automatically loaded up windows 8 which is not even fully installed yet. so now it keeps booting into the windows 8 version of the windows needs recovery page and it says "the Boot Configuration Data for your pc is missing or contains errors(\boot\BCD)"

so i have tried making a windows 7 repair usb but i cant access my hard drive for some reason, is just doesnt recognize it. so my question is how can i access my harddrive or its partitions. i'm certain i can fix this if i can do that. i also dont want to open up my laptop to take the harddrive out.

Thanks in advance

You ran the installer?

DO you mean you made an iso file and are doing this by booting dvd/usb ?

If you are, there is an option "repair my computer" at bootom left of the "install now " screen .

Give that a run and see if it helps.

oh yeah should have mentioned that I have windows 7 on a usb and i'm trying to either do a fresh install(not my favourite option) or just repair windows(not working out so far). I have tried the "repair my computer" option many times but it hasn't done anything. It won't let me install windows 7 again it says "restart the computer and let it boot into an older version of windows and then try upgrading again"(paraphrased)