I guess I just don't know when to quit. Anyway, I played around with it some more, it seems what's making it be completely dead on power-on is related to memory frequency. I have 2400MHz memory but when I bump it higher than 1866 it won't start.
Do I need to adjust some voltages or something? CPU voltage or memory voltage?
I read the guide that mkenyon posted, but since I have a specific problem (too high memory frequency causes computer not to boot), I'd like to understand specifically what affects this, as solving problems one by one is better than just changing every number all at once. I did try setting all the numbers as the guide suggested, but it didn't seem to help. My Motherboard apparently has a set of Debug LEDs on it which might help diagnose the problem, but my manual doesn't list what the codes mean and I can't find it online.
On another subject, people earlier suggested to disable sleep mode. I don't even seen an option for this in my BIOS. The APM (Advanced Power Management) menu only has options for when to WAKE the system. I can do it in Windows by having Windows set to not put my computer to sleep after being idle, but this seems like a subpar solution, because some else using my computer could accidentally hit Sleep from within Windows start menu. Is there a bios setting to disable sleep mode?
I found something onlien that suggested you don't need to actually disable sleep, but instead disable "PLL Overvoltage". My BIOS doesn't ahve that option, but it does have the option to change PLL voltage directly. It defaults to Auto (no clue what that means), would entering a value manually here be the same as disabling "PLL Overvoltage"?