Landlord Tenant

Can a landlord evict existing tenants after purchasing a building?
Landlord just purchased a building that is already occupied by tenants. Can Landlord evict the tenants now that the building belongs to him/her?
Can a landlord legally turn off a tenant's utilities for unpaid rent?
Tenant is behind in rent and has received a letter from Landlord threatening to have the utilities turned off if payment is not received. Can Landlord legally turn off Tenant's utilities?
Can a landlord legally lock out a tenant for unpaid rent?
Tenant is extremely behind in rent payments. Landlord has decided to change the locks on Tenant's apartment. Can Landlord legally lock Tenant out of the apartment?
Does a tenant have to allow apartment showings before lease expiration?
Landlord and Tenant have a written lease agreement for an apartment. The lease agreement will expire in one month, and Landlord wants to show the apartment to potential tenants. Does Tenant have to comply with Landlord and allow strangers to enter into his apartment?
How much notice does a tenant at will need to give to move out?
There is no written agreement between Tenant and Landlord. Tenant pays rent on a month-to month basis and is considered as a tenant at will. Tenant got a new job, and will be moving. How much notice, as a tenant at will, does Tenant have to give Landlord?