Possible Grounding issue on a network switch?

[Mr.Si]

Hi all,

We have a customer who've recently been having problems where their network switch has just stopped working. Now, being an IT Support company, we know how to deal with this to get it working, however we've never seen a particular problem as this...

Basically, all the cabling was ruled out and the only thing that fixed it was that a particular desktop, which was plugged in to the switch, as soon as it was unplugged the switch instantly became alive again. Oddly, the computer was not even on and thus not a usual type of problem with an IP Address clash. When a laptop was plugged in (on battery) it worked fine. (The mains for the laptop is doubly insulated anyway, so no connected earth pin).

We told the customer not to plug the computer back in to the network.

However, it's happened again this morning and it's now turned out that another computer was doing the same thing and it was also off.

We were wondering if therefore there may be some sort of Grounding error with the switch being on a different circuit to the computer(s).

Anyone ever seen anything like this before?

It's most odd!