Is it a software problem or a hardware problem?
Is the wacom tablet brand new?
Make sure you install the software first before you plug in your wacom tablet. I would make sure and read the provided directions when you open the box.
I would uninstall all the software on your computer. Then, I would reinstall the software on it again. Then try to plug in the wacom tablet again. You may want to plug the wacom tablet in other USB ports. Then test it out, basically "trail and error." I wish the best of luck for yah.