Every time I unplug my laptop for any amount of time, and then plug it back I get 'plugged in, not charging.' There are absolutely no problems with my battery or power cord, I know because each one is less then a year old. I periodically check the cord for tears there are none. Its come to the point where I loath having to move my laptop because I know its gonna be useless for days to a week before it naturally accepts the charge again. I've looked all over the internet but everyone assumes the problems is the battery, the cord or some internal thing; I need another solution. Also the uninstall, then reinstall thing in device manager doesn't work for me either.
Plug the charger in, remove the battery and turn it on. Once it boots up put the batter back in after cleaning the contacts with an alcohol wipe or erasor tip. The charge light should come on ... leave it to charge. Once charged run it and deplete the battery a bit then plug it back in and see. You might want to also clean the charger socket with an old toothbrush to make sure it doesn't have any lint or obstructions in it.