what is the procedure to start hardware and computer sale and support business

Find a niche. Are you going to be cheaper than BestBuy? Are you going to give better service than GeekSquad? Are you going to advertise more than they do?

Are you going to offer your services in a language that they don’t?

Seriously, find a niche. Find some area where you can compete, because it isn’t price, and it isn’t service.