PLEASE HELP !!!

Hello. If anyone can help me, I will greatly appreciate it. I have searched everywhere in the Discussions for help and have found none.

I usually connect to a lan network over a ethernet cable. I have never been asked to input any numbers or addresses (DNS and such), it just automatically works.

Today I downloaded the Security Patch and afterwards RESTORED THE PERMISSIONS in my laptop. After that, when I plug-in the ethernet cable the computer WILL NOT detect any connections.

I can connect wirelessly, but not through cables...WHAT CAN I DO??