Thanks Dillon_642, that was the answer for me.
The question is ... why were all those greyed out devices showing in the first place?
Well, one answer might be if you have been using System Restore a number of times (as I had). I can only think that when System Restore restores your system back to an earlier restore point, then it somehow adds all these extra unconnected devices so that they show up in Device Manager.
So if you use System Restore, be sure to check after a restore that there are no extra greyed out devices showing in Device Manger. If there are, delete them.
Hope this helps.