USB port question - works for one device, doesn't work for another

[#Darren]

I have run my mouse dongle from every USB port except 1, the reason being it won't work from that single port.

The port in question does work because I have plugged my external hard drive into it and it ran fine.

Now when I plug the mouse dongle in it does seem to recognise it (makes a little "plonk" noise), but the usual "installing software/hardware" type notice does not pop up like it did with all the other working ports, and the mouse will just not work.

Any ideas on what this means? Is it possible a fault on the motherboard connection, or is there some other explanation?