Well I suppose I better provide an update in case anyone else is having the same problem. Snuck my wife's laptop when she wasn't looking and tried it on that. Had to install all the android sdk stuff, the java stuff, and the kies thing eventually after a few hours of waiting it worked. I had to leave it plugged in for ages before it would install all the drivers it needed BUT it did eventually work. I think the problem with the desktop is that it's too old (nearly 10 years now). The laptop isn't a whole lot newer but it is.
So I would think if you have a newish machine you will (eventually) be alright, but saying that I did find LOADS of people over the net complaining their samsung this or that wont work on their PC. Still working away at trying to get it to work again on the desktop but I'm giving up hope.

The weird thing is before the 'update' it just worked right away and was fine. Now it seems to want to use this MTP protocol thing to connect and there doesn't seem to be a way around it. I did manage to root the device through the laptop and that was what I wanted to do. For file transfers it works over the home network via wifi and connects to the Pc and kies ok. So as a last resort, if anyone is still trying to connect and only wants to transfer files to/from PC-Phone, then wifi over the home network will work. Don;t know if that is actually of any help, but there it is just in case.