Jim, It may be that the name of your wife's machine was accidentally changed (I hope. if not, then I too am confused). To check (the computer, not my amount of confusion):
1. Open/launch your System Profiler
2. In the System Profile tab, in the second box from the top entitled “Startup device” is the name of your wife’s machine. If it matches, e.g. it is the + sign, you may be assured all is well and that it is only a result of an accidental name change.
If you wish to change the name back to the way it was, just double click on the name part HD icon and make the name change as you would with any folder/file.
BTW, you can only make this change if File Sharing is turned off.
HTH
Harv