If your Windows XP computer is not recognizing your flash drive, its likely that you computer simply is confused as to what drive letter to assign to the memory stick. Fortunately, the fix is a simple one. This trick also works when your computer refuses to recognize a USB drive or other removable storage device.
First, hit Windows+E to open an Explorer window.
Select “My Computer.”
Right click and choose “Manage” from the contextual menu. This will open a window called “Computer Management.”
Select “Disk Management”, which is under “Storage”
On the bottom right side of the window, you’ll see a list of all of the storage devices currently attached to the computer. If your flash drive is listed there, that’s great—you can fix the problem. If not, this solution won’t work.
Right click on the drive listed in that window. This will bring up a contextual menu. Choose “Change Drive Letter and Paths.”
This will bring up yet another window, which will show your “missing” drive. Choose “Change” at the bottom.
Another window will pop up. This one will have a drop down menu on the right hand side. Choose a letter “higher” than the one currently assigned to the drive. If it’s “E”, for example, choose a letter between “F” and “Z.” Its probably best to pick one toward the end of the alphabet.
Once you’ve selected a drive letter, a warning message will come up saying that “Changing The Drive Letter of a Volume Might Cause Programs No Longer To run.”
That’s OK. It’s likely that all you’ve got on the drive is data. Click on Yes.
That will return you to the Computer Management Window.
Your drive now should function properly.