Wifi connected n internet access.. but after 10-15 mins fails

Hello,

The First issue was when the Video streaming (e.g. YouTube) would stop downloading unless I refresh the page but when I refresh, it stop downloading again. The same Issue is with downloading files; on Firefox, whenever I start downloading a file, it stops downloading half way through (at random points of the download) but when I pause it and then resume the download, it carries on but stops again. Its as if the connection just drops and comes back again. THIS IS REALLY FRUSTRATING >:(

The Second issue which I recently started to experience, is the internet keeps stop working after some time when I've booted up the Laptop, when the internet stops working, I restart the Laptop but the same issue happens again (Internet works for 10-15mins and stops working) but the connection is totally fine; its connected to the internet with full bars but for some reason its not working.

I've tried installing all the latest Drivers for the WIFI Adapter etc. and I have also tried to scan the whole system through Kaspersky Internet Security 2013but no LUCK :'(