Normally I do it in this order:
3-clean ram edge connectors
4-jiggle the gpu
5-clean the gpu edge connector
6-if the processor is a land grid array type (LGA), clean contact, if its pin grid array (PGA) then remove and reinsert a few times
7-if all that fails then back to the ram for swapping banks and removing sticks.
8-if all that fails and I'm sure the psu is fine then I would probably blame the motherboard.
Thanks for that flowchart, i'm studying to be in the IT field, and this will really come in handy, despite it being a bit dated. When i get a blank screen, i will do a restart, and maybe even a soft reset. If that leads to the same thing, it's probably a bad connector, or GPU, or the mobo is dying.