I’ve almost killed myself and my machine (Toshiba Sat Pro P200-1K9 - Vista) fighting to solve this for 3 weeks in a row, having my laptop just on AC during all this. Tried everything that could google, reset bios, bought new battery and mains adapter etc.
Below is step-by-step how I managed to make it work but it still does not make any tech sense to me:
Starting stage – laptop on mains only, battery taken out, Power plan Balanced (important!):
• Change Power Plan to Saver
• Turn off laptop
• Unplug the mains cable. Now your comp is totally unpowered.
• Press start button and hold it for 10-15 secs
• Plug the mains back in and boot the computer
• Insert the battery back on.
Worked for me, it started charging. Although interesting thing – once I decided to change the Power plan back to Balanced – it all happened again (“plugged – not charging”) and I had to re-do this voodoo once more. So it seems to be sensitive to this change.
Anyway, I hope it will help at least someone else.