OS X Mail was crashing, bad hard drive was thought to be the problem.
The hard drive replacement went very well. It took about 1 hour to get to the hard drive. It took me an extra 3 hours to reassemble because I failed to connect the LCD cable securely the first time. The step by step instructions for iMac 2134 were perfect. After replacing the hard drive, MAIL still crashed. It required a call to Apple support to fix the problem.
When disconnecting the LCD cable, I loosened the circuit board it attaches to which allowed me to get my fingers under it enough to pull it out. There was too much slack in the ribbon cable just to push down on it. When reconnecting it, I loosened the circuit board and used a Pink Pearl eraser to cover the wire tips on the outside of the board. This allowed me to exert enough pressure on the plug without making my thumb bleed. It also kept me insulted from the capacitors. I found the torx screw drivers at Home Depot. The suction cups worked great. Be very careful setting the glass back on the iMAC. There are metal studs that break off easily.