Recent notes:
Vista laptop/notebook power management issue: 'plugged in, not charging' when battery is at a low level. On some systems, this tip has enabled users to charge their batteries: disconnect power cable, change 'Power Options' setting from 'balanced' to 'Power saver' and plug cable back in — the display should change to 'plugged in, charging' (you may have to repeat this process several times as vista stops charging again).