The CJVS came from @corey all I did was map the buttons to Mame default and defined the exit parameter. If you can't find his post I still have the files and didn't try a long button press. I wasn't sure how to code for that to be honest. :)
I had one similar white screen symptoms and it ended up I needed to replace the CPU. I had no way to test that until it was replaced, so it's a bit of a gamble.
The Niko multis hard drive will be readible in your computer. It will see different drive letters and directories for the directories described in the read me.
A lot of people are scared the first time they discharge a monitor. Once you pop your first anode cap you will realize it's not such a big deal. 95% of the time there is no charge.
I just have a big screwdriver with an alligator clip and done it a hundred times now.
The VRam addresser, you still shouldn't get a black screen I don't think
Those usually have an extra brown socket under the main pins. You can remove the extra socket if those are the pins that you bent. You can take that socket off and either put on another one or just put it directly in.
You went from an error message to a blank screen? That's very odd.
Since you took the board out. Check the edge connector. On pac games it's common for them to get worn out.