After our file server goes down because of a power failure the network drives that have been mapped in windows don't work. But you can also not delete it and recreate it. So I found a way of remapping it.

Go to the drive of folder you want to remap. Right click on it and select map network drive. Select the appropriate drive letter. The file folder will be blank but click on the drop down and select the drive folder that was previous ther. Select finish