Blue Orb is on the fourth floor if I recall correctly, but current release is bugged. I assume Red/Green orbs aren't in your inventory even if you found them? Most likely you'll need to use the console to fix the issue (or watch for the patch which will release on July).
I hate to keep bothering you, but I got the blue orb and opened the hidden room, was I supposed to eat the rotten fruit or not? I ate it and it said I had a strange power welling up and then it took me back to town with a skull in the corner, did I die or something else happen? thank you again for putting up with me.
Yeah, that's what it's supposed to happen. You pass out from it, but awake with a newly found power (which is the ability to learn up to 12 spells). There's no death in the game (aside from game over screens, which are rare). The power you unlock carries over in the sequel as well, so it's a good thing to have whether you are currently doing a magic-oriented playthrough or not.