I have a problem with a batch of Dell optiplex 980's, for some reason the Main boards fail at a alarming rate. According to Dell it is the memory controller that fails. Error Lights 1,3,4 are on nothing on screen, power led solid blue about 10 error beeps! Dell tech replaced the main boards and all is fine for a while but same problem persists. Also according to Dell level 6 tech, it could be over heating, I had some fun proving them wrong, two PC's sealed in a box , hammering them, Temp between 85 Celsius - 90 Celsius in the sealed enclosure, optical drive started melting, cooled the PC's for a day and powered back on, no problems!! Does any one out there maybe have a issue similar to this on the optiplex 980, main board failures?