This is very important fact to be aware of when you are using your laptop. Most laptops generate a lot of heat when they are ON, so you need to be very careful by keeping them cool. There are Laptop Coolers in the market specifically designed for laptops. Nowadays, almost everyone has at least one laptop at home. Never leave the laptop for long period of time on any Cloth Type Surface, and it's always better to use flat table and raise the laptop side with some kind of support below it to get air ventilation at the bottom side.
 
Most important of all, you should never leave the laptop running in any room without someone's attention.