For the past several months, the Macbook has had a random shutdown glitch. This has
now been corrected by installing an Apple update. Just install the Macbook SMC Firmware Update 1.1 and this will fix the random shutdown issue. Even if you’ve had warranty repair in the last few months, you should also install this update. You should even install this 
update if you haven’t experienced mac tech issues to prevent future computer problems.
It is better to upgrade your Mac OS to the latest operating system update. For instance, if you’re running Mac OS 10.4.7, you should upgrade first to 10.4.8. Then, install the patch above.