Especially when using Windows 7, the installation of a new USB-device can sometimes need several minutes, because this operating system always tries to find and download the most recent drivers, even if none are to be found.
So, if you get a notification for a running device setup, open it and then click on the instruction to skip downloading the driver software just as marked in the screenshot. This should speed up the setup process considerably.
Then wait for the setup process is complete. Afterwards you should be able to find the signature device in the used software.