Windows – Win7: How to solve: Unidentified network/No Internet connection problem

It's been a few days now that I have gotten problems and problems with my network connection, though my other computer works fine!

The problematic computer is operating with (PC2)

Windows 7 Professional

The running-fine computer is running (PC1)

Windows Vista Business

The problem occured when I turned off my Cisco Catalyst 3500 series switch so that I can move it to another location (5 feet away). I then recoeecnted the Ethernet cables and my cable modem to the switch.

The PC1 then reinitialized the network, found the settings and reconnected properly! Internet is then running just fine as if I had never touched it in my life! Great!

I can't tell the same with PC2, sadly. It began to identify the network, then set it to Unidentified network over and over again though I have tried solving with the troubleshooter. Here's what I did so far:

I read this linked in answer article to know what's NLA.
What settings does Windows use to determine network location?

I have also read this:
LAN – Unidentified Network (No Network Access) on Windows 7

I have also tried:

1. Setting the DHCP Broadcast Flag to 0 so no more broadcast;
2. Running a Powershell script that was suppoed to set all Unidentified network to private;
3. Went and change manually Unidentified network setting from "unknown" to "private";
4. Forced ipconfig /release, typed in a fake IP in my Local Connection, saved the seetings, then clicked the "Obtain an IP automatically option, and ipconfig /renew;
5. Setting proper DNS IP though PC1 is set to obtain them automatically (and works, not PC2);
6. Disabled the adapter, uninstalled and reinstalled it, and enabled it;
7. To stop the NLA and related services with no luck (didn't solve my problem);
8. Rolledback to previous working settings/configuration with a restore point, and it netiehr solved the problem.

Many of the above-mentioned tries come from ServerFault.com and I simply can't find the questions anymore, so please believe me, I DID search! I've been working for about 6 hours on the problem, that is, probably becuase I am no network nor system administrator.

Any one who has something relevant is welcome to answer and help me. I'm desperate. =( I just want it to work!

While trying the ipconfig thing, it said that the DHCP request timed out. I tried to ping some other IP addresses as well, and it seems PC2 is totally lost. I can't find a solution, I have done everything I could, I knew, and learned for the last two days.

Thanks for your help!