If there are many objects ( 3 or 4 ) , it will stop working whenever i jump to rendered mode , my laptop is a little disappointed with core i3 , windows 8 , using intel hd 3000 ( i think this is the problem ) , what i have to do now ? replace a better laptop or any speed-up solution ?
It is hart to tell what you mean by stop working. Do you mean it crashes or is your rendered image completely black?
In both cases I would assume it is because a high poly count of these 3 or 4 objects you mentioned.
If your render turns black and you are using cycles it might be that these high poly objects fill up your memory. If you are using your gpu you can switch to cpu to fix that problem.
If blender actually crashes on you while using cpu rendering you can try to reduce the amount of polies in your scene.
Hope that helps. You did not give me much information to work with so I just guessed that this was the problem if its not some more informations would be helpful.