Hey abz, you'll identify with this.  I got back from lunch to find everyone panicking, they couldn't get email or on to the internet and stuff.  The boys were doing stuff on the server until I pointed out that some users were OK and others not and suggested maybe a switch had gone down.  Sure enough one had, so patch users onto other switches and away you go.  I've just ordered a replacement 48 port gigabyte switch.  You see experience wins every time. LOL.