|If the flash drive shows up in Disk Management , but it doesn't show up in My Computer or Windows Explorer, there is probably nothing wrong with it but the partition table data on it has been damaged. Usually that problem can be fixed by you using certain programs to fix the partition table data damage. |
(Control Panel - Classic view - Administrative Tools - Computer Management - Disk Management)
Troubleshooting USB device problems including for flash drives, external drives, memory cards.
See Response 1: