This can happen to you, when you insert your USB drive to your computer, then Windows detects it, but does not show the drive icon for it in My Computer. The culprit here is Windows which is unable to allocate a Drive letter for your USB drive.
Why USB drive not shown in My Computer?
Windows detected the USB drive, but unable to allocate the drive letter for it, this behavior can happen to new USB drives you just brought.
What’s the fix?
The Fix is we have to change the drive letter of USB Drive that is already shown in disk management service. For that,
1.Click Start>Run>type diskmgmt.msc and press Enter.
2. Select USB Drive>right click on it, and click Change Drive Letter and paths
3. Now a window comes up to add, change and remove drive letters for the USB drive.
4. Click change and from drive letters drop down menu select a letter that is not allocated to other drives in My Computer, and click OK and click Yes to confirm to continue from the warning message
5. Now new drive letter is allocated to your flash Drive and will be shown in My Computer.
6. Now you can access your pen drive without any problems.