It is most likely a service that is disabled rather than a device driver. Go to Start / Control Panel / Administrative Tools / Services / and scroll to any entries concerning bluetooth and make sure they are both set on Automatic and Started - if not, do so (and if they have dependencies that aren't automatic and started, do the same with them). There may be more than one so check the whole list. When done, if you made any changes, see if bluetooth is now working.
I hope this helps. If not, I need the manufacturer, make, and model of your computer. If the bluetooth device was purchased separately, I need the manufacturer, make and model of that as well.
Good luck!