I don't remember the law firm that started my divorce proceeding how do I find out what firm started it and if it's still good

If you have any court documents it would be listed on there. If you don't have any then you will have to get at least one from the courts and they will be listed on it.

I don't remember the law firm that started my divorce proceeding how do I find out what firm started it and if it's still good

If you know the court (state, and county usually) in which the divorce would have been filed, you may be able to look it up online.