Problem with wifi, stop working

Hi,
I have an Acer aspire 5750G i3 2.10Ghz etc.
This week i have a problem with my wifi connection.
The problem starts with a strange noise from the speakers and then the wifi stop working..... BUT when i go at black screen or at sleep mode the wifi works fine! After 3-4 seconds stop working again...
i have searched at google for solutions but nothing, so i tryied to fix it by myself.
I have done format but the problem exists !!!!!!!!!
so i opened the case... but inside its fine... all the cables are correct connected and .... the problem exists....
Can you help Me????? I dont know what else to do!!!!

Start over fresh to run Acer Restoring a system to factory load

or get the superior Clean Reinstall - Factory OEM Windows 7 following the steps closely especially about how to handle drivers in win7.

Nothing!!! It didnt help!!!!

What did you try, and exactly what happened?

We can't help you if we don't know the exact failure point, error message or other information besides the lame "It didn't help."

Plug in by ethernet cable, run Windows Updates to install all Important and Optional Updates after enabling Automatically get recommended drivers and updates for your hardware (Step 3). Make sure the wireless is turned on, check if driver is installed and working in Device Manager.

If the problem still exists after a full format and reinstall of windows, then it sounds like a hardware problem, try a USB wifi stick or get the the wifi card in the laptop replaced

It hadnt appeared any error message.... I was playing LoL and i heard a weird noise from my speakers and my wifi just stop working. i downloaded this, and it didnt found any problems.... okay, i am going to ask help from a technician...

You downloaded what?

What does it say under the Wireless Network adapter in Device Manager?

Atheros AR5B97

and i have noticed and something else... when my wifi stop working, i have problem also with my ethernet.... it stops to work at the same time with wifi...

Does it say both Adapters are working in Device Manager?

In Control Panel>Network and SHaring Center>Change Adapter settings, are both adapters enabled?

When you hover the mouse over the connection icon in bottom-right System Tray, what does it say?

Rightclick on the connection icon in bottom-right System Tray, run Troubleshooter.