Ubuntu 14.04 doesn't connect to Wi-Fi or search for it.

Is the system fully updated using the wired connection?

Please provide the output as stated in https://help.ubuntu.com/community/WirelessAskAtLaunchpad but in step 3 do not create a new question, but paste everything as a response into this one that you have already created.

Manfred: I think we should merge

https://help.ubuntu.com/community/WirelessTroubleshootingProcedure

and

https://help.ubuntu.com/community/WirelessAskAtLaunchpad

into 1 document.

What do you propose?

https://help.ubuntu.com/community/WirelessTroubleshootingProcedure

is more up-to-date in my opinion....

@Mark: absolutely no objection

And when this is done, maybe the command
cat /etc/modprobe.d/* | egrep '80211|acx|at76|ath|b43|bcm...'
should be changed to
grep -E '80211|acx|at76|ath|b43|bcm...' /etc/modprobe.d/*
This would have the benefit of listing the name of the modprobe.d files that contain the respective reference (and ends calling egrep which is deprecated)

@antonio:
Please do not get confused that your question document is misused by us for a discussion that does not help you with your problem (even although it is related to such cases).

This question was expired because it remained in the 'Needs information' state without activity for the last 15 days.

Antonio, if you still need help, please provide the output of the long command in step 2 of https://help.ubuntu.com/community/WirelessTroubleshootingProcedure