Oh boy I thought for sure you fixed it stemz05.
Let's step back a little bit, you say it was fine and no problems before installing the south bridge water block and cleaning. If this is correct are you sure you didn't damage anything on the motherboard when doing these?
The fact that it does boot sometimes and works outside the case would indicate the motherboard is ok, I mean the motherboard either works or it doesn't. I got my hands thrown up in the air with a big ? hanging over me now.
The freezing could be a power issue or your ram is not fully stable, but running at default settings you shouldn't get freezing.
Those codes are not very common and the fact that it stops on different codes really has me befuddled. I don't like to point fingers at the motherboard without extensive testing preferably with other components. It could be the psu or power connections even though you have a very good psu. Double check all your power connections including the pcie power cables are secured into place and on the psu end too. You could inspect each cable to make sure all the pins are in place.
When it does boot can you game or use your pc for hours on end with no problems?