[edubuntu] WIfi shows connected on ubuntu but disconnected on router.

Hello Everyone,
I had just installed edubuntu 14.04 on my lappy(hp pavilion g6 2226 tu). The matter is that whenever i connect to my wifi router, it works for 4-5 seconds and then it stops working. I mean to say Ubuntu is showing connected with wifi but when i checked on router, it was not showing there , also,obviously, i cannot access the inteet. .af
There is one more issue. Whenever i start lappy after shutting down, it start blinking rapidly. After this when i power t off and restart, it works correctly. i know it's not hardware issue as i tried it on my lappy before i installed it. Please help
P.S: I am new to ubuntu.