I was importing some photos to LightRoom today and my MBP shut down without warning, I tried to switch it back on but just got the white light flashing on the front. The power was attached and the battery was nearly 100%. I took the back off and re-seated the RAM which I upgraded soon after purchase and this seems to have resolved the problem but I am slightly worried now that the machine has an issue. Has anyone else experienced this? Are there any quick diagnostics I should run?