I have laptop hp it suddenly shut down int 30 when I on

Further information would be useful.
What operating system & specs.
What where you doing, etc..

Trying running the laptop without the battery, if that's not the case try checking the temp on the PC,if it gets really hot clean out the dust, or check your fans, processors will automatically turn off if its gets too hot to avoid damage.

My VAIO was doing this about a Month ago. Found a Fan On Ebay With Heat sink, for under $10, and that included S+H. Great deal. A couple of hours later(figuring out how to take it apart, and reassemble), it was working like a charm.