This isn't the typical issue of the battery being dead. Situations: Power Plugged In PRE bootup: MacBook turns on as you would expect it. The moment you pull the plug, it shuts off. Sleep mode works fine. Not Plugged In PRE bootup: When the power is unplugged, I need to hold the power button down for about 5 or 6 seconds, if I release it, it completely shuts off. If I hold it until the grey screen, it runs as normal. If I plug it in at this point, it works fine and I can plug / unplug it and it wont shut off. If the Mac then goes into "Sleep Mode" - it complete shuts off. If I press the power button, I get the reset/sleep/shutdown message - if I select sleep, the Mac looks to go into sleep mode, but then it seems as though it completely shuts down as I need to restart it from scratch. I've tried the SMC a PRAM reset without change. I called a local Mac repair shop, and he said he knows exactly what the issue is, and would be around $250 to fix it. Obviously he wouldn't tell me, thats his business. Any help would be greatly appreciated! Thanks!