Most of the USB memory sticks we use at home have drive letters assigned to them which is handy for shortcuts to open programs such as email. The letter stays regardless of which USB socket they are plugged into EXCEPT for a Kingston Data Traveler Elite 3.0. It's hardly new but 32GB in capacity. I can assign a letter but only for one socket, in any others it comes up as "K" which is the first free one. Changing the letter in another socket causes it to revert to "K" in the others.

I've looked at System>Hardware>DeviceManager>USB>MassStorage (including "hidden") and removed them all and started again. From here you can find the location in "regedit" but I've no idea how to proceed.

The nuisance seems to follow on any PC but as it's fast and robust I've ordered a DataTraveler G4 to replace it. This series seems to co-operate OK and I'll use the Elite for general purpose storage and transfer. The best way to avoid any more headaches I feel.