Can I upgrade my logic board?
I want to upgrade my logic board my current system is:
Apple iMac A1225: Intel Core 2 Duo Extreme 2.8 Ghz 24" (Al)
Last digits of my Serial Number: EZCV
Model A1225 / Mid 2007 and Early 2008 / 2.4, 2.8, or 3.06 GHz Core 2 Duo processor
James you currently have the most powerful model in this series of systems. So upgrading the logic board here is just not possible.
The best solution here to sell your current system and buy a newer model (new or used) that meets your needs.
Just so you know there are a few things you can do to improve your systems performance. Like upgrading the HD to a hybrid drive (SATA II 3.0 Gb/s) as well as up the memory to 6 GB. With these improvements you should be able to get another year or two more out of your system.