Hi Billy,
Thank you for posting your query in Microsoft Community!
Based on the issue description, it appears that mouse and keyboard stopped working after connecting Coby MP3 player and there is no Human Interface Device listing in the device manager.
I can understand the inconvenience you have experienced. I will certainly help you out with this issue.
Let’s try these methods and update us with the results.
Method 1: Hardware devices not detected or not working - Mr. Fixithttp://support.microsoft.com/gp/hardware\_device\_problems
Method 2:
This issue may occur if the drivers are corrupt. You can try uninstalling and reinstalling your mouse and keyboard drivers. Download the latest drivers from the manufacturer’s website and install.
Update drivers: recommended links.
http://windows.microsoft.com/en-US/windows-vista/Update-drivers-recommended-links
Update a driver for hardware that isn't working properly
If the issue persists or you have any further questions on Windows, please do not hesitate to let us know. It is our pleasure to be of assistance.