Updated from 32 bit to 64 bit Ultimate, now saying invalid activation

Hello, I'm using a computer I built myself two years ago, back then a friend of my brother who works in IT assisted with the build and installed an OEM copy of windows 7 ultimate 32 bit he had via USB, the copy was genuine and was activated. Earlier today I decided to upgrade from 32 bit to 64 bit after hearing that a 32 bit key works on a 64 bit installation. I attained an ISO for 64 bit...