Probook 4510s charging problems


Sep 16, 2012
Whilst using my ProBook 4510s on battery, it suddenly died. Plugged into the mains, and it works fine. However, the battery does not charge and the battery / mains icon says "On AC Power" - it used to say "Charging xx% yy minutes remaining". In teh three days since this happened, the battery power meter has progressively shown less and less charge, dropping from 38% to the current 25%.
I don't think this is a battery problem - any clues, and is it worth having a 3-year old ProBook repaired? Or is there a simple fix I can do?