No network connection after plugging in Logitech Cam

I recently plugged in a USB Logitech Cam (~4 years old) into my D600, and that seems to have preciptated all sorts problems, including (a) "serious error" blue screens resolvable by a video driver roll-back, (b) extremely sluggish system performance and running out of virtual memory (c) inability to get my network connection going again, even in "Safe Mode with Netwok Support"

The really weird part is that the Logitech Cam, when first plugged in, appeared as a network connection that I was not permitted to disable. Its ip address was all single digits, like 1.0.4.0.

Any ideas about why the USB camera showed up as a network connection?

And suggestions how to get "Safe Mode with Network Support" running? I now have lights on my router and LAN port indicating a 100Mbps connection, but repairiing the connection gives DHCP failed. My LinkSys router / DSL connection works fine for other PCs.

Thanks in advance!

(D600 1.4GHz Centrino 1400x1050 XP SP1 40GB disk; 15Gb free, McAfee Anti-virus )