rd2002

simply restart ur laptop will solve this problem~
i have no idea y this happens as well~

rd2002

or, you can try to reinstall your os (operation system).
sometimes corrupted files system files can create such problem.
also, do you use p2p programs like bt/emule etc.? if you do, then, i suspect it is the p2p programs that cause the problem. because sometimes those programs pull too much system resources, other programs can be unresponsive due to the lack of resource.
the 3rd possible situation might be the router and/or modem, be it a dsl/cable modem. sometimes after intensive downloading sessions for an extended period of time, the hardware might be overheated. so, simply turn off the device(s) for about 30 seconds and turn it back on will help, too.

rd2002

laptop is built for convenience, not for heavy duties...
try not to use your laptop for these p2p programs...
i think u should be fine as long as u don't use p2p programs along with surfing online.

rd2002

if so, i think it might be the quality of your integrated network card that causes the problem then. once it is overheated, it is very likely your network card will become dysfunctional, or at least partially dysfunctional.
also, don't reply too much on the laptop cooler because it helps a bit, but it does not solve the overheating problem.

rd2002

as i said in #7, laptop is built for convenience, not for heavy workload. so, there should be no solution to that as long as you use it the way it is.
although i said laptop cooler doesn't solve the overheating problem, it does help to lower the temperature a bit. so, you might want to use a cooler when you use your laptop.
but, again, using laptop for an extended period time, without putting it to sleep mode and/or turning it off to cool it down, will significantly shorten the lifespan of your laptop.
of course, it is your laptop. you have the final word of how and when you want to use it. but, just wanted to remind you that it is not a good idea to use it for too long per sitting.