Wi-fi switches from working to non working?

[fattty]

Got to make this quick. Im at a friends connected to his wifi. It connects fine with 4-5 bars out of 5. (windows 7)

Everything works fine for like 30 seconds then the wifi stops working and i see a little yellow triangle sign kind of the like a yield sign over the wifi signal in the traybar and it says no internet access even though it has an "excellent signal strength"? Then maybe a couple minutes later it will start working (not always) and repeat the whole process.

This hasn't happened in the past, only yesterday and today. What is going on?

Please list all possible problems :/

 

[MindoverMaster]

It's your wireless card or its drivers that are bad. I had a similar problem with my Dell laptop. A new card fixed it.

 

[fattty]

Well worked fine all day at home on my home wifi connection. Im using the friends connection right now. Keeps working and then not working then working etc.