Win xp U disk does not show the solution of the drive letter

A few days ago, when I was helping someone repair the computer, after I plugged my USB flash drive into the computer, the computer recognized the USB flash drive, but I could not see the corresponding drive letter when I opened "My Computer". Go to Disk Management in the "Administrative Tools" (enter diskmgmt.msc in "Run" and press Enter), you can see the disk, but no drive letter is assigned. Manually assign a drive letter g, but open "My Computer" and still no U disk drive letter. Enter g:\\ in the address bar to indicate that the file://g:/file could not be found. If the USB drive is formatted in Disk Management, the prompt cannot be formatted and the volume is not enabled. If you right click on the newly allocated g disk in Disk Management and select Resource Management, you will not be able to find g:\\. But in the Windows console (command prompt, enter cmd in "Run" and press Enter) to enter the U disk, you can operate normally (copy, delete, open the file). The strange thing is that you can see the corresponding drive letter when you plug in the mobile hard disk.

Final Solution:

Go to the system directory C:\\WINDOWS\\system32\\drivers See if there is a "sptd.sys" file. Remove it and reboot. problem solved! Note: This "sptd.sys" is not included with Microsoft Windows.
Another possible reason:

1, there is a mapped network drive in the system, resulting in the drive letter can not be assigned to the U disk.

Solution: Disconnect the mapped network drive.

2. The drive letter is hidden.

Solution: Enter the registry (regedit.exe) and go to the "HEKY-CURRENT-USER\\Software\\microsoft\\windows\\currentversion\\policies\\explorer" branch. Find the key value "NOdrives" that exists in the path and delete it. Log out and log back in. (Not the NoDriveTypeAutoRun key value).

3, U disk problems.

Solution: Reformat the USB flash drive. It is best to format low-level, find a U disk tool online.

4, it is not good, then the last move: re-install Windows XP!