Let me be more specific about what's happening...

Battery indicator applet on this laptop says that the battery is not worn-out, it's good. It has a wear-indicator-scale of 0-100% "good", and it shows 100% "good", with 58 charge cycles in the battery's lifetime.

Charge meter (not the same thing as the wear indicator above) seems to work fine. Shows full charge, can see it slowly decreasing as the battery gets used up.

However, battery gets used up a bit faster than expected. Looks from the speed of the decreasing of the charge meter that it would die in less than an hour instead of the 2+hours estimated.

But somewhere during the drain, say, around 88% charge... BAM the laptop shuts off completely. No warning.