Windows Vista Ultimate Freezes and Restarts When I Plug In My Internet

I recently plugged in the ethernet network cable whilst the computer was on because I wanted to access the internet. The mouse froze right away, and after a few seconds of unresponsiveness, the system restarted. Now, every time I unplug or plug in the network cable, the computer does the same thing - it hangs and restarts. The thing is, I have had this Sony Vaio Type Z laptop with Vista Ultimate for almost three months and we are always connecting/disconnecting the ethernet cable, and this never happened before.

What can I do to remedy this problem? Has a driver or something like that become corrupt?

I read on another forum that if you reduce your ethernet card speed from 1000MBPS to 10 MBPS the problem will not occur anymore, but my question is why is this alteration required now once we have been doing this for long with no issues? I don't even know how to change my ethernet card speed anyway.

? What do you mean??? The problem isn't when the pc is off, its when its on and I want to use the internet! Did you read my post??