External storage devices such as USB flash drives are commonly used to store and share data across computers. In general, these devices are automatically recognized when plugged into the computer, but there are some instances where external devices do not show up in your My Computer folder.
If your computer has suddenly stopped recognizing your external hard drive, but still shows some signs of a connection (i.e. the sound of a whirring noise is heard upon insertion), it is very possible that your USB ports have been disabled. Here's a quick tip on how to locate the missing flash drive.
How To Find Your Missing Flash Drive in Windows
To enable a disabled port, first click on Start > Run.