Start with removing File sharing
Control panel > Network connections > Right click on your network card > Properties > Select File sharing ..., then click on Uninstall (or remove)
On the same window, click on Install > Service > File sharing... and validate all the windows
Always, on the control panel, double click on Folder options > View. Make sure that the last case "Simple file sharing" is on.
Right click on a folder > Properties > Sharing, and activate the sharing for all folders.
C u !