I had to fix a problem at my dad's company...
"The network was broken."
It was a NetBEUI network connecting some windows stations - it has been running for years - and now suddenly the nodes couldn't find eachother.
One of the boxes (windows 2000 iirc) had 2 network cards, one for the network, the other not used for anything (not even connected). Disabling the latter - not even touching the former - fixed half of the network.
There was another box that couldn't find any other node in the network. This happened to be a box of which the ps/2 mouse broke. It had a usb mouse connected but since it was windows 95 it was not supported. I removed the usb mouse and attached another ps/2 mouse. This fixed not only the mouse but also the box could suddenly find the other boxes again....
Windows really does suck.
And the worst part is: even though all is fine now, I have no clue for how long it will work, and what will be the cause the next time it will be broken?