1. Determine which player slot was deleted: the player at the top is in slot 1, and the player at the bottom of the list is in slot 5.
2. Open My Documents, then open the folder named LDW
3. Look for and open the Virtual Families folder (the actual name may vary, depending upon where you purchased the game). Do not attempt to open the savegame files, to prevent the possibility of corrupting any of them. The savegame files in that folder are named Virtual Families1.ldw through Virtual Families5.ldw, and correspond to each of the player slots. The backup savegame files are named Virtual Families21.ldw through Virtual Families25.ldw, also corresponding to each of the player slots.
4. Verify that the savegame file for the deleted player is no longer present (e.g. if the player in the 3rd slot had been deleted, there should be no file named Virtual Families3.ldw).
5. Rename the backup file to make it the primary savegame file (in this example for the player in the 3rd slot, you would rename Virtual Families23.ldw to Virtual Families3.ldw).
6. Launch Virtual Families to verify that the player has been restored. The game may not be as current as the one that was deleted, depending upon how recently the backup file was updated, but you won't lose all progress on the deleted player.