Drive was failing.
All went well until I tried to connect the flat monitor cable to the motherboard. I never got it connected, and in the process, I ruined the cable. The iMac is junk. It is my fault. The tutorial from you was great. I just didn't pay attention when I unplugged the cable. I also ruined the connection on the display.
I do have a nice hard drive with the old drive cloned on it.
I really like your site.
I don't think anything would have to be disconnected except the drive connections. At least on the iMac I have.
Just use a short Torx driver to remove the two screws holding the drive. Lift it to disconnect the three connections add remove the drive.