Try clearing cmos, unplug PC from wall with switch switched to on, remove shiny battery, press and hold power button for 30s~, plug back battery, then plug back pc to wall and try to power it up, the PC should power up regardless of the ram is it into the slot or not, first try without ram, then try ram into slot that wasnt that ram into it.
Also check for Ram slot pins if they are blacked out.