What are the status lights on the Fb3?
If they're green at PC start then try removing and re-installing QS.
You can do this quite easily without any loss of data.
Go to the root folder ie. C drive > QS2 (or wherever you've stored it if different) and delete the programme icon. Empty recycle to be sure.
Unpack a new version of QS from your downloads, copy the icon then paste it back into the QS2 folder where the old icon was.
You usual short cut from the desktop or task bar will work and when you start QS you'll have a clean version.
If this doesn't work it could be the drivers in which case you need to remove and re-install them. Remove drivers using the usual windows system management route. In Win 7 that's Start Menu > Control Panel > Administrative Tools > Computer Management > Device Manager > Pangolin Devices > Properties > The remove drivers tab.