Macbook shutting off suddenly

I’ve got a late 2008 model Apple Macbook. It’s worked flawlessly since I bought it the same month it came out, until just last week it began randomly suddenly shutting off for no apparent reason.

The firmware is all up to date, I’ve reset the SMC, I’ve verified and repaired all the disk permissions, I’ve been monitoring the temperatures of the components with iStat Pro (all seems within normal ranges), the fan reads (and I can hear it) that it’s running at the prescribed rpms, EVERYTHING appears to be perfectly fine and yet it continues to randomly shut off.

Any ideas before I give up and head down to the Genius Bar?

If it does it when it’s plugged in, it’s going to be a short or break somewhere, and you’ll need the genius bar. If it only does it on battery power, then I’d suspect your battery is going to the great mercury/lithium grounds in the sky a little ahead of schedule. There’s a bunch of circuitry on the battery that can hide the fact that it doesn’t hold a charge well. That model still had replaceable batteries.

Timewinder has step 1. If it does it plugged in, head for the store.
If it’s really hot on the flat place above the escape key, you may have the heatsink glue thing happening. Google it. Then head for the store.
If you suspect the battery, download http://www.coconut-flavour.com and get some intel. Or try another battery.
The new solid body Macs with the built-in batteries are cool.

Oh yeah…unplug it, pull the battery and then hold the power button down until it beeps. Can’t hurt.

I had a MacBook that did ths. Turned out the fans were not working properly and it was overheating. Wwn the procesor reached a certain temperature, it shut off instantly as an emergency measure.

There was a firmware fix for it. The yech guy said if that hadn’t worked the fan would have had to be relaced.

It’s been plugged in 99% of the entire time I’ve owned it.

The temp on all points never gets up to a critical level.

The firmware is all up to date.

Guess I’m off to the Genius Bar.

Thanks anyway guys.