Computer won't find Wi-fi connections

Hello All,

I have a samsung N130, a while ago the connection dropped suddenly and couldn't find any wi-fi connections. I'm using a D-link Usb dongle and I can find all the networks.

After trying everything, I was convinced that the Atheros chip is faulty, so I bought a new one, but it didn't work...so I tried my Atheros on an another netbook and it worked fine.

It can't be an OS problem since at the beginning of the problem i did a factory settings restore and tried Ubuntu, all of them had the same problem.

Sometimes it is able to find near wi-fi networks only but won't connect.

So if anyone knows what's the problem i would really be thankful, it's very annoying!

Cheers all!