I have a SR MBP 2.4 ghz, 4 gb memory and I am having a little problem. When I run it off the battery sometimes it will shut off spontaneously. When I check the battery status it has 3 green lights. When I try to restart the computer it gives the initial chime then shuts off. When I attach the power cable it will boot up just fine and operate normally. The battery reads 68% charged. In addition when the battery is at full capacity the light in the power adapter (which should be green) shuts off. Any suggestions? Thanks.