Probook 4510s charging problems

Steve_B

Honorable
Sep 16, 2012
1
0
10,510
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?