Hi there babieduquesa,
It will be great if you could provide some more information on the issue you are facing.
I guess you can perform some basic troubleshooting steps like: connect the drive with another USB cables as well as to another computer.
If the issue persists, you need to go to Disk Management and see whether the drive has a drive letter assigned, healthy partition or file system. Depending on that, you may need to use some data/partition recovery software or assign a drive letter.
Hope this will help,