What do you mean by invisible?
Is she still in the portrait box with a picture, just can't be seen walking around?
Is her portrait box green and can't be seen walking around?
Is she still showing up in the relationship panel, but has no portrait box nor walking around (like she moved out, but you know she didn't)?
What do you mean by tried edit town?
Did you split up the household so she goes to the clipboard, then merge the household so she's part of it again?