Help,couldn't connect properly to the internet using wireless.

hai,i,m running a netbook intel atom 1.6Ghz windows 7 1 GB Ram.
i had this issue going online after formating.
i've installed the drivers and all but i still manage don't know why i couldn't
solve this issue.
The problem is,my wireless lan goes dead everytime after online for about 15 minutes or later.
i don't even remember when i managed to get full access online internet for 6 or 12 hours straight.
My modem is on,everything is fine,i had a desktop it connected,my iphone is on wireless
so does a xperia x8 and a mini galaxy GT-5570 also able to recieve and goes online. No issue
at all. Only my netbook is having issue connecting it. And i notice, everytime when i charge
the battery of my netbook,it goes dead pretty quick,especially when its heating up.
When its hot or charging my netbook,i couldn't enjoy using it for less than 15 minutes.
Then,i have to sleep it or hibernate it so then it will recieve my modem line again.
its been a pain in the neck. I never had this issue before formating my netbook.
Any suggestion or ways to solve this issue on my own without sending it to workshop?