Laptop WiFi issue...

my laptop connects to the WiFi just fine (Acer aspire 5740) but every 5-20 minutes the connection turns off, its still connected to the WiFi but not receiving internet access.

the issue is not the WiFi as it is working perfectly on my desktop... what could be the issue? and how do i fix it?

• Has been happening since I downgraded from windows 8 to win7 ultimate.
• If I turn WiFi on and off, it temporarily solves the issue.