On many levels you can think of the SONOS controllers as a simple remote control, very little is stored in a controller. The SONOS players manage the minute to minute system operation details. When you renamed your PC, as far as the players are concerned, you moved the library to another location. Sometimes the players might figure out a rename, but this is not guaranteed. Using a SONOS controller, go to Music Library Settings, delete your old library, and setup a new library with the new location. This will not modify your files in any way, it simply points SONOS to the correct share.
You may have some trouble with SONOS Playlists. I don’t know if they will be aware of the move.