Thanks for your reply. Let me try to make the problem a bit more clear. My problem with the wi-fi happens only with the imac. My bookpro and my iphone and ipad int he same place as the imac access the internet with no problem.
The problem in the imac is that it changes network configuration withe the following status message appearing in the Open network preferences:
Wi-Fi has the self-assigned IP address 169.254.22.50 and will not be able to connect to the Internet.
when it should have
Wi-Fi is connected to REIS and has the IP address 10.0.1.3. or something like taht to work
The problem is that the imac keep shifting sometimes in minutes from one configuration to the other.
Is there any suggestion or solution?
Looks like we may want to pull the System Configuring folder and see what happens...
Go to MacintoshHD, then go to Library/Preferenes
Drag your SystemConfiguration folder into the trash (it will ask for a password).
Then re-start so the OS creates a new folder with defaults. Re-join your network, and see what happens.