How to price a Support Contract?

[baccart]

Hello,

I have done corporate support as an employee, and now doing retail support. I was approached by a retail client to support his company. He mentioned about 25 Laptops, plus some desktops. I have no clue as to how to approach in building a list of what support he thinks he needs, or he will really need. Can you point me to where I could get this information (questions to ask), and to price this contract for a monthly support contract?