No. Unless they gave you a new key.
can a landlord change the locks on a commercial building without notice
You do have some legal rights when renting a house. The house should be clean and liveable, the landlord should tell you when he is coming over to fix the house, the landlord cannot have the locks changed.
No, a landlord cannot change the locks for abandonment if the tenant has not moved out of the rental property. Changing locks without proper legal process could be considered an illegal eviction and may expose the landlord to legal consequences.
Not in any state I know of.
You need to check with the landlord about that. You cant just change the locks on a property that you do not own.
Try talking to the landlord to see if you can give him the rent and see if you can have the lock key?? :) It's worth trying.
I can only answer for Massachusetts, but I think you can. The landlord has a right of entry, but he should get the permission of tenant, and the tenant has a right to be there at the time. If the landlord needs to get in during an emergency, perhaps he should be calling the police.
Not in any state that I know of. Most state codes require that the landlord provide a mailbox, and locking it would be a breach of quiet enjoyment.
A landlord could get in trouble with the husband for changing the locks, but that seems unlikely, especially with a letter from the wife asking that they be changed. There is also no reason why the wife cannot change the locks herself.
Yes, it is their house now, not yours.
This will depend on your state law: in some states the landlord is allowed to keep your property; in others they must put it in storage; while in others they must put it on the curbside
Not necessarily. A landlord must have locks installed which must secure your rental dwelling. They don't have to be deadbolt.