Having a website with only 1 page is NOT a good idea. That being said, having all of your important information on the main page (hours & directions with a map, basic price list, reviews, products, etc.) is nice. Just be aware that your bounce rate will affect both your Google ranking and how much you pay for AdWords. If Google sees that people just go to your main page and then close the window or hit the back button, it will lower your quality score. I have a client that insisted on making a 1 page site. I warned him against this, but he didn't listen. He came crying to me a few months later because he was paying upwards of $16/click in AdWords, and before he was only paying $4/click. Why? Because his quality score tanked.
Also, having a specific landing page is very important. If someone Googles "laptop screen replacement" and they land on your main page that talks about "Cloud services and IT management," changes are they'll wonder why Google brought them there and hit the back button. That equals WASTED MONEY and a lost customer.