[wellylug] eth troubles

[E.Chalaron]

Hi all

I have a slight issue here...
I turned off one of my PC a couple of days ago and since the following is 
happening :
My switch does not want to know anything about this machine (though the link 
seems Ok and I have some packets sent). All other machines are Ok with the 
switch.
Now this happened not so long ago and I left the switch off overnight, came 
back and everything was Ok, not now ..
The eth card works fine with a hub.. <- ???
I relocated the cable on the switch : no way.. all other machines can be 
unplugged replugged without a problem, just this one ... :-(

where should I look ?
E
lost