Hi,
First thing is, if this is an audiobox USB (original) it is a port specific device. This means it ONLY works on the port you installed it in. If you plugged it into ANY OTHER PORT after the installation on the original port, the device tried to install on THAT port also. You will likely need to uninstall and re-install the AB USB. There is a number of articles in the Knowledge base (
http://support.presonus.com/hc/en-us ) about these issues and solutions. (
http://support.presonus.com/hc/en-us/categories/201264183-AudioBox-Family ) I HIGHLY recommend you check these articles out.
Make sure you register all your Presonus gear in your "My Presonus" account, and make sure ALL your software and drivers are on the LATEST versions appropriate for your hardware and software. This is the SUREST way to insure a problem free experience. We continually vet the devices and software from the accounts to insure trouble free operation.
Make especially certain you have the latest versions of Universal Control for the AB USB and you FOLLOW the installation instructions! I know at one point you needed to install the software and WAIT for instructions to plug the AB USB in, if you had it plugged in when you installed the device it would fail on SOME systems.. remember, we are all using divergent systems with myriad configurations and this makes it difficult to solve the problems without knowing exactly what your system is. We have asked that you provide system specs in some situations to help us get a solution for you.
If NONE of these things help, create a tech service ticket so a tech can get you up and running. Also check out the the Knowledge base, and the user forums which are here to help!
Best regards