You should try some basic troubleshooting.
1- Connect the power adapter to the wall directly.
2- If the computer is a desktop, connect it on the back USB port (directly to the PC, not through a hub).
3- Make sure you hear the connection sound windows makes when recognizes a USB device.
4- Go to "Disk Management” to verify if the drive shows up there.
If the drive shows up in disk management but it is not seen on Computer, then it means the partition is corrupted and you will have to format it in order to use it again. Please note that formatting the drive will delete all data stored on it.
Before formatting, it may be possible to still extract the data utilizing data recovery software. There are several kinds of Data Recovery software available. If you do a web search for Data Recovery it will yield plenty of data recovery software options.