Laptop Freezes And Then A Small Beeping Noise?

i have an acer aspire 5738z and i am using windows 7 ultimate. every time i boot it up it works fine until i start getting onto internet. when i am using internet say, streaming videos on Internet or playing an online game or watching a movie online, the laptop just freezes. sometimes it freezes for like 2 secs but sometimes over 10 minutes. and then sometimes it comes back on again as normal or i will have to manually restart it from my end. i also tried to find any faults using a registry checker and couldnt find any although i am not pretty sure which is the best registry cleaner to be used. i also find that sometimes the laptop beeps just once before it unfreezes.