Put chicken broth, potatoes, celery, onion and pepper into slow cooker. Cook on low for approximately 6 or 7 hours until vegetables are tender.
Add bacon to slow cooker.
On stove, combine cream, Velveeta cubes, shredded cheese and yogurt. Cook over low to medium heat until hot.
Pour cheese mixture into slow cooker, stirring constantly.
In separate bowl, combine cornstarch and cold water, mixing well. Slowly add to soup, stirring all the while. Cook 30 more minutes and serve. Salt and pepper to taste.