It is legal to work for your self business as a computer agent who repair computers without a diploma?

Hi I am 24 years old and i had repair almost for 6 years computers for my friends and family ,I have a fluent knowledge in computer repair,but i don’t have any diploma. I am thinking to start a self business in computer repair ,but i do not know if it is legal to do [...] http://bit.ly/nJ28C8