Windows 7: Unable to detect wireless but visible on smart phones, tv

Hi, sorry for the trouble. I am currently facing a problem with my new internet connection after upgrading to an internet with faster bandwidth. I am able to detect the wireless network using a smart phone, tv and the person who installed my connection is able to connect to the network.

However, all of our computers cannot detect the wireless network. Our wireless card is working well because we are able to see other wireless network around us.



There are something common with all our home computers:

1. We have all connected to our old wireless internet connection
2. We are able to access the new internet connection using LAN

There are no error messages involve in this problem. The person who installed my said it has something to do with an IP clash with my previous saved connection, hence not being able to detect the newly set up network through wireless connection.

The person suggested me to just send it to the shop, but I hope someone here could enlighten me with a solution. I tried searching the net about this issue but can't really find a solution to it. Thanks =)