Processor overheating and fan noise

Dear Sir/Madam

I have a Dell Vostro 3578 laptop which has recently started to perform inefficiently. The fan makes irritating noises and keeps buzzing all over, also the processor turns really hot even after basic browsing. I always use my laptop on the table in an air-conditioned room still, it heats up to 70 C while browsing. Waiting for your assistance.