Hi John
Take a look in Disk Management and see if the drive is listed there
This may help -
Log on as administrator or as a member of the Administrators group.
Click Start, click Run, type compmgmt.msc, and then click OK.
In the console tree, click Disk Management. The Disk Management window appears. Your disks and volumes appear in a graphical view and list view.
Try allocating a different drive letter to the drive if it is there.