My cable modem is connected to my computer using a cross over cable (well, at that's what it seems like to me - it says "X over" on the RJ45 connector). We wanted one more computer to be able to access the internet at the same time so we put an Edimax 8-port switch and plugged the cross over cable from the modem into one of the switch's ports. Then we bought two straight through cables and plugged both into the switch also.
It worked for about two weeks; we could surf simultaneously and play network games. Then one day the switch wouldn't turn on. Since the switch was still under warranty, we brought it to the vendor who confirmed that it was not working.
I don't know if I'm wrong, but could the damage have been done by mixing cross over and straight through cables into the switch?
Here's more info on the switch (I'm using the 8-port model):