Hello Becky -
By design, laptops just aren't as efficient as desktops when it comes to cooling. Components are bunched together in a small space and the fan is usually underpowered and doesn't move a lot of air. Generally speaking, laptops need to be used on a hard, flat surface like a tabletop and not on a pillow, bedspread, or even a lap. Vents and fan will surely be blocked adding to the heat build up. Many people even use a laptop cooling pad to help with air circulation. Laptop cooler - Wikipedia, the free encyclopedia
But there's another consideration that may prompt you to take the laptop back in for warranty service. It's possible that a heat sink or thermal paste was improperly installed during production. No amount of cleaning will correct that kind of problem. Some additional thoughts: HowStuffWorks "How to Keep Your Laptop Cool"