Check this LINK,then "Why does the battery icon keep changing?",then," Choose low and critical power levels for your battery."
Tom
On my new Toshiba Satellite A200-AH7 laptop running Windows Vista Home Premium, when I hover over the battery icon, it only shows the percent remaining but not the time. I tried to download widgets that tell you the time remaining but they don't work for me either.

Chowhound
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