If the system will not cool at all, check the breaker/fuses to make sure they are not tripped. If the system will run, but isn't blowing cold air, check the air filter in the furnace to make sure it is clean. Check the outside unit to make sure that the coils are clean. If either the air filter or outside units are dirty, that is a good indication you need annual maintenance to keep these systems clean so call our office to schedule this service. If the filter and outside unit are clean and it still isn't blowing cold air this is an indication you need to have the system checked. Call our office at 608-437-3666.