If merely plugging the cable in causes the system to shut down, I would think "hardware" versus "software/infection". Have you tried using a different ethernet cable? Maybe an electrical short.... Or is your "network cable" a USB cable instead of ethernet? If so, try an ethernet cable instead of USB..
I am curious WHY you unplugged the network cable in the first place?
If you plug other computers directly into the same router port, does it cause an issue?
Hope this helps.
My Dell computer started blue screening every time I plugged the network cable into it. It also kills the network for all the other computers on the Linksys router wired or wireless. I have a Hyjack this file and system info file for it if needed. I have ran CA virus scan, Malware scan spybot search and destroy in regular and safe mode.
Should I insert the hyjack and info file here?