Frankly for '2 years' the RAM has been installed in the wrong DIMM slots, and after 2 years of dust -- pff the B1/B2 slots should be cleaned. A couple ways: 1. High pressure air, 2. Isopropyl alcohol: dampen the RAM's contacts, insert, remove, clean -- repeat x2 per slot, remove and allow to dry ~5 minutes.
IF using the old (working) set fails as follows then your MOBO is the culprit:
CPU: | A1 | A2 | B1 | B2 |
CPU: | OLD | blank | OLD | blank | ; Tested A1 & B1 (fail) = MOBO problem ; NORMAL Dual Channel configuration
CPU: | OLD | blank | blank | blank | ; Single Channel
CPU: | blank | blank | OLD | blank | ; Single Channel
Normal Installation, even the same RAM -- after time uses different IC's and the following installation is highly recommended:
CPU: | OLD | NEW | OLD | NEW |
CPU: | NEW | OLD | NEW | OLD |
Since you said CPU: | OLD | OLD | blank | blank | worked, what about CPU: | NEW| NEW| blank | blank |? This is to see if the NEW RAM is good.
Unplug the power cable and take the battery out for 30 minutes. Then put the battery back in and plug the cable back in.
Sometime in that 30 minutes, push hard on the RAM. Not so hard you think you will snap it and not at an angle, just firmly and straight down. If the clamps reach up and grab the RAM that doesn't mean its all the way in.
They can handle a good bit of force so push till you are confident it doesn't go in more.
Final Conclusions - 1. MOBO - I've seen this enough times. ; 2. Short - Aftermarket HSF with metal to MOBO contact and/or Standoff's causing a grounding short. Some cases have 'punch-outs' and not the thin screw type. ; 3. Bent CPU pins - this can cause a Channel to drop-out.