Mind Your Business

I dropped my laptop at the store where it was purchased for it to be sent off for service. I went up to the counter and gave the lady siting behind it my laptop, but I forgot the power cord in the car so I ran outside to get it. I come back in and a man asks me what is wrong with it. I told him what was happening. He says "it may just be( such and such). I can show you how to do (this, that, and the other)."
I'm thinking that he doesn't work for the service department. He has not turned on the computer to see what I am talking about. Which means that you can show me how to do all this stuff and it may not fix the problem. His talking starts to make me angry. I know I was giving him one of my looks.
You may say, Oh he was trying to be helpful. I say I bought a warranty for this specific reason. So I shouldn't have to do a darn thing to it put turn it on and enjoy it. In the kindest tone I could I told him No. I was not going to do anything.
Mind you it was Sunday and I had just left church. I was thinking all sorts of nasty words I could say. But there is power in the tongue so I refrained. I think he made me mad because I didn't nor did the lady at the service desk ask him for his help. Did I get mad probably for no reason? Maybe. Do I feel Bad? No. It could have been worse.