I've had this issue for a long time.......so I thought I'd ask and see if anyone knows the cause and solution :-
When my router gets disconnected from the net, the router itself soon reconnects with no problems. But, my PC seems oblivious to the fact that it has reconnected. The little world symbol does not re-appear for the internet. Only re-booting the PC gets that back. It's been this way ever since I bought the PC three years ago.....my previous PC would automatically detect any router re-connect.
Well....as I don't get disconnected that often its not a major issue, but it is annoying when connection problems do occur, as I then have to restart the PC on every disconnect. I have no idea what the cause of this is....whether there is some setting that will fix it.
A similar ( maybe related ) issue is that sometimes I lose the world symbol and internet connectivity even though the router says connection is just fine.