Ah, a notebook - sorry about my wrong assumption! Many notebooks have the air intake underneath, and (pretty obvious, I know) these should not be used on your lap or any other soft surface that would block it.  

But I've seen many a so-called "laptop" computer with its cooling air intake on the underside! 

Izi

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)