We won't recommend booting up with an iso file cd, as long as we don't know what iso it is. Not a Windows 8 one, that's sure, because Windows 8 doesn't fit on a cd but needs a dvd.
I'd have a look at the user manual or the dell site to find out how to come into the Windows 8 repair/refresh/reset options and how best to use them.
i have a new problem. the other day my pc was working fine. but now i try to login to get into my pc. the little circle just goes round and round for like 5 mins that the screen turns black. the only thing on the screen is my curser.
if i boot of up with my iso file cd i will lose my 8.1 product key!! is there anything i need to do. its a dell