One problem that I witness all the time is USB memory sticks taking a mapped network drive letter i.e. F:. I usually email them this guide to changing the drive letter.
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1. Click on the Start button and then select Control Panel.
2. Double click on Administrative Tools then double click on Computer Management.
3. You should now see the following screen, at this screen in the right hand panel double click on Storage then double click on Disk Management (Local)
4. At the following screen in the right hand panel you will see a list of drives names and there drive letters. As you can see below your USB stick will show up as a removable disk or if it has taken your network drive it will show up as a network drive but will show the Mega Bytes as what your USB Memory Stick Is i.e. 128MB
5. Right click over this area and select Change Drive Letter And Paths then at the next screen click on change.
6. At the next screen click on the downward arrow as shown below select the drive letter you want then click OK then click on Yes.
7. Now close all of the open screens and go into My Computer and you should see the USB stick as a drive letter.
