Hi CGMIDD,
Issue appears to be due to motherboard failure. As a last resort, we can try reseating the memory modules. Please refer the following link for the Inspiron 1520 user manual that has instructions to reseat memory modules: http://bit.ly/XgCJKH
If issue persists after reseating memory modules, motherboard needs to be replaced. You may contact our expired warranty services to purchase/replace the compatible parts. Please refer the following link that has contact details for our Expired Warranty Services: http://dell.to/14FoBtb
Do let me know the results.