You should be able to use the drive after removing it from the pool. Is there a prepare for removal option next to the drive? Select it and then once the drives says ready to remove select remove.
I wonder if it's part of a storage pool. What do you see in "Manage Storage Spaces"? You can find it in the control panel. Also maybe you could try a 3rd party software like MiniTool.
You could connect one of the outputs on your provider's router to the input on your own router. Then disable the wireless on the provider's router so that only your own router is broadcasting.