Just remember, when troubleshooting one: take everything off that you can, including memory, and then see if it notices there's no memory. If it doesn't notice, the problem is the motherboard. If it does notice the lack of memory, add everything back, one piece at a time, and attempt to boot in between.
The secret to troubleshooting is simplification.
First, remove the user from the equation. This is harder than it may first appear.