I decided to describe this problem by picture.
Here we go:

http://www.freewebs.com/vikysha/problem.jpg

I hope someone will understand what's going on.
I'm actaully sure that reinstalling the OS on DESKTOP PC would solve the problem, but I don't want to do that too fast.

I seem to have the same type of problem. It just started recently. If I open the Network Connections window in Control Panel, hit F5 to refresh every 4 or 5 seconds, the connection in question is intermittantly plugged in, then unplugged in. Very frustrating.

I have ran diagnostics on the hardware and installed known good drivers. Scanned for viruses and spyware, as far as I can tell, my system is as clean as a whistle.

I have fixed that problem already... What I did is I just bought new LAN adapter because old one was I guess only 10mbps and that why it was causing the problem...