Recently I re-installed Windows 7 and installing drivers was a bit tricky, especially the drivers for the AMD graphics. If you go to AMD's website and attempt to download the most recent drivers it won't work. It will state that you have incompatible hardware. Downloading the drivers from HP's support page works, just make sure to get the ones for the "HP Pavilion DV6T-6100 CTO Quad Edition".
Officially my system is a DV6T-6000 CTO, but HP has done a shit of a job posting the right drivers for the right system. The drivers listed for the DV6T-6000 do not seem to work properly. I also had trouble with the wifi+bluetooth, but with the 6100 drivers I got my problems fixed.
Maybe this is the driver that should have been installed in all of those faulty HP DV6T with AMD 2GB DDR5 6770M with 1080p screens.
Download it at:
HP - Software Drivers for HP DV6T-6100 CTO Quad Edition (choose your 32bit or 64bit OS)
HP - AMD High-Definition Graphics Driver For AMD Radeon HD 6490M and HD 6770M