Blowing air injudiciously in to the ducts of a laptop is not advised as you can do more harm than good. There are multiple components that can break with the force of the air and you also risk re-distributing the dust and debris in to small tight airflow channels where it will block cooling efficiently even more.
If you have been blasting it with air only a disassembly of the outer laptop case and chassis to expose the motherboard and internals and proper clean will solve your cooling issues.