PC would not boot or show BIOS on either screen. I guess I should plug in
the Beep speaker.

Maybe ultimate upgrade path would be to plug in Continuous long beeps:
Graphics card not inserted properly(total 8GB) and then upgrade to 12GB.

Comments?

'Continuous short beeps:' Power error. ****, not again?

Comments?

Now with removal of 2 x 2GB RAM sticks:

Continuous long beeps: Graphics card not inserted properly.

Something we can work on. But why?

Comments?