The car makes a squealing sound when I start and sometimes when at rest.
My car has 161000 miles.
My car has an automatic transmission.
This is likely a squealing belt which is a common problem with engine drive belts. When you start the engine (especially when it is cold), the drive belts are instantly subjected to the strong torque of the motor turning them at a very fast pace. When this happens, if the belt is loose or not pliable enough (usually can be fixed with a bit of belt dressing), this will cause the belt to squeal a bit. To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your location to diagnose your squeaking belt firsthand and help you make the right repair.