Did you uninstall the old video drivers?
How did you do it?
Did you delete the old video card folder and empty the recycle bin when you finished uninstalling the driver?
Did you install and run Ccleaners registry section of the software to clean out what the uninstaller missed in the registry?http://www.filehippo.com/download_ccleaner
All the above should have been done before
you rebooted to install the new driver.
Sometimes updating a bios will fix problems like this, but don't do it unless you have someone with you that knows how to do it. You can brick the motherboard and have to send for a new bios chip if things go wrong. The newer motherboards have procedures now where you can recover from a bad flash without sending the chip in to be flashed by the manufacture.