For anyone else having problems with their USB memory drive not being recognised by Windows XP, here are a couple of suggestions that might just resurrect the missing drive letter.

The first common problem is that the USB device is trying to use a drive letter that is already allocated.

To check this go to ‘Disk Management’:

• Start -> Programs -> Administrative Tools -> Disk Management

or

• Start -> Run -> Open diskmgmt.msc

Your USB drive should be listed as a removable device. If the drive letter is not assigned or is the same as an existing device then right-click over the disk, “Change Drive Letter and Paths…” and then change the drive letter.

If the drive still doesn’t appear in the “My Computer” folder, this more complicated solution from Microsoft’s Knowledge Base could well fix the problem (it did for me anyway).

“A computer that is running Windows XP cannot detect a USB thumb drive, an Apple iPod, or an external hard disk drive” – http://support.microsoft.com/kb/925196

You attach a USB-based device to a computer that is running Microsoft Windows XP. Then, you try to scan for hardware devices. However, the computer may not detect the attached device, and you may not see the device in the My Computer folder.

loadTOCNode(1, \\’symptoms\\’);In my case I deleted both the LowerFilters and UpperFilters registry values from the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\4D36E967-E325-11CE-BFC1-08002BE10318} registry subkey, rebooted my PC and the USB memory drive appeared!